Tumors of Muscular Origin 18 P.C.Seynaeve, P.J.L

18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 293

Chapter

Tumors of Muscular Origin 18 P.C.Seynaeve, P.J.L. De Visschere, L.L. Mortelmans, A.M. De Schepper

Contents puted tomography (CT) and, especially, magnetic resonance imaging (MRI) – have brought some progress in 18.1 Introduction ...... 293 this field. 18.2 Classification, Incidence, and Clinical Behavior . . . . . 293 18.2.1 Tumors of Smooth Muscle ...... 293 18.2.1.1 Benign Smooth Muscle Tumors ...... 293 18.2 Classification, Incidence, 18.2.1.2 Malignant Smooth Muscle Tumors ...... 295 and Clinical Behavior 18.2.2 Tumors of Striated Muscle ...... 295 18.2.2.1 Benign Striated Muscle Tumors ...... 295 18.2.2.2 Malignant Striated Muscle Tumors ...... 296 Since imaging techniques lack specificity, it is not possi- ble to classify tumors by their radiological appearance. 18.3 Imaging ...... 299 18.3.1 Imaging Studies Other Than MRI ...... 299 For this reason we will classify the muscular tumors on 18.3.1.1 Plain Radiography ...... 299 the basis of histology according to the WHO classifica- 18.3.1.2 Ultrasound ...... 299 tion of soft tissue tumors: 18.3.1.3 Angiography ...... 299 ¼ Smooth muscle tumors 18.3.1.4 Scintigraphy ...... 299 A. Benign tumors 18.3.1.5 Computed Tomography ...... 299 1. Angioleiomyoma 18.3.2 MRI Findings ...... 299 2. Deep leiomyoma References ...... 309 3. Genital leiomyoma B. Malignant tumors Leiomyosarcoma (excluding skin) ¼ Skeletal muscle tumors 18.1 Introduction A. Benign tumors Rhabdomyoma Generally speaking, tumors of muscular origin are not a) Adult rhabdomyoma common.The radiological literature is limited mainly to b) Fetal rhabdomyoma case reports [17, 27, 38, 55, 59], and even when series of c) Genital rhabdomyoma soft tissue tumors are reported, the number of muscular B. Malignant tumors lesions remains low [33, 49]. In two fundamental papers Rhabdomyosarcoma based on lesions seen by the Armed Forces Institute of a) Embryonal rhabdomyosarcoma, spindle cell Pathology over a 10-year period, Kransdorf reported rhabdomyosarcoma, botryoid rhabdomyosar- 311 benign tumors of muscular origin (leiomyomas) coma, anaplastic rhabdomyosarcoma out of a total of 18,677 benign soft tissue tumors, or b) Alveolar rhabdomyosarcoma, solid rhabdo- 1.7% [32]. Among the 12,370 malignant soft tissue tu- myosarcoma, anaplastic rhabdomyosarcoma mors, there were 1,039 leiomyosarcomas (8.4%) and c) Pleomorphic rhabdomyosarcoma 239 rhabdomyosarcomas (1.9%). The recently concluded Multicentric European Study on Magnetic Resonance Imaging of Soft Tissue Tumors 18.2.1 Tumors of Smooth Muscle observed 26 tumors of muscular origin out of a total of almost 800 randomly reported cases [14]. Although 18.2.1.1 Benign Smooth Muscle Tumors muscle tumors have been well described and classified histologically, imaging techniques have remained of Superficial or cutaneous leiomyomas must be divided limited value in specifying the tissue diagnosis of these into two entities: leiomyomas derived from the arrectores masses. However, the newer imaging modalities – com- pilorum muscle complex and genital leiomyomas [19]. 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 294

294 P.C.Seynaeve, P.J.L. De Visschere, L.L. Mortelmans, A.M. De Schepper

a b

c d

Fig. 18.1Ia–d. Angiomyoma in a 46-year-old man with a long jacent normal muscle on T1-weighted MR images (a, b). After standing swelling in the left hand, recently increased in volume. gadolinium contrast injection, the lesion shows no obvious en- a Axial spin-echo T1-weighted MR image. b Sagittal spin-echo T1- hancement (c), but on STIR MR sequence there is a very high sig- weighted MR image. c Axial spin-echo T1-weighted MR image af- nal intensity (d). Illustration of an angiomyoma with nonenhance- ter gadolinium contrast injection. d Axial STIR MR sequence. At ment on T1-weighted MR images after gadolinium contrast injec- the ulnopalmar aspect of the ﬁfth MCP joint, a small, nodular, tion and very high signal intensity on STIR MR sequence well-deﬁned mass lesion is seen, with signal intensity equal to ad-

The arrectores pilorum leiomyomas lie within the clear. Whether these lesions develop as a result of vessel dermal connective tissue. Most lesions consist of a cen- invasion by one or several endometrial tumors, or tral zone of smooth muscle cells and blend with the sur- whether they are formed by a proliferation of smooth rounding dermal collagen and adjacent pilar muscle. muscle cells within the vessel wall is still debated. The These leiomyomas are solitary or multiple painful nod- lesions develop mainly in promenopausal women. Clin- ules with a diameter of 1–2 cm. These small papules can ically they present as abnormal vaginal bleeding and eventually coalesce to a fine linear pattern in the same pelvic pain. In about 50% of these patients, the uterus is dermatome. They may be associated with dermatitis enlarged. In certain cases cardiac symptoms may occur herpetiformis, HLA B8, premature uterine leiomyomas, or even predominate owing to the presence of tumor in increased erythropoietin activity, and multiple en- the vena cava or the heart. docrine adenomatosis type 1. They arise most frequent- Deep leiomyomas histologically have a rich vascular- ly in the extensor surfaces of the extremities. ization, which may mimic soft tissue sarcoma. The pres- Angioleiomyoma, angiomyoma, or vascular leiomyo- ence of stippled, plaque-like, or larger mulberry calcifi- mas are histologically divided into three subtypes: solid, cations similar to those in uterine leiomyomas has been cavernous, and venous. All of these subtypes contain described in deep-seated soft tissue leiomyomas, espe- nodular conglomerates of smooth muscle cells and cially in childhood [18, 36, 38]. Deep leiomyomas are thick-walled vessels (Fig. 18.1). less frequent than subcutaneous leiomyomas. Deep These are rare; they account for about 5% of all be- leiomyomas can occur in the deep parts of the extremi- nign soft tissue tumors. These tumors develop most fre- ties . They affect both sexes equally, whereas leiomy- quently in women in the fourth to sixth decades.Most of omas of the retroperitoneum or abdominal cavity occur the solid histological subtype tumors occur in the lower almost exclusively in women. leg as slowly growing solitary masses of several years’ In our series (databank of soft tissue tumor of the duration.Pain is a prominent feature in about 50% of all University Hospital Antwerp), only one histologically reported cases. proven leiomyoma of the deep flexor compartment of Intravenous leiomyomatosis consists of benign the arm was found (Fig. 18.1). smooth muscle tissue nodules that grow in the veins of Leiomyomatosis peritonealis disseminata is another the myometrium and occasionally extend into uterine rare entity and is characterized by multiple smooth and hypogastric veins. The pathogenesis remains un- muscle nodules situated subperitoneally throughout the 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 295

Chapter 18 Tumors of Muscular Origin 295

abdominal cavity. It is not accompanied by any par- jacent tissues is a relatively early event, while in arteries enchymal disease within the abdominal organs and (pulmonary artery) the tunica elastica is usually pre- does not extend extra-abdominally. Leiomyomatosis served and invasion of other organs is absent. Vascular peritonealis disseminata only occurs in women of child- leiomyosarcoma is a rare tumor. The inferior vena cava bearing age, is frequently associated with pregnancy or seems to be its primary site and accounts for 50% of oral contraceptives, and tends to be frequent in Afro- recorded cases, while the greater saphenous vein ac- Americans. counts for 25% and the bulk of the rest arise from the Genital leiomyomas are histologically heterogeneous femoral, internal jugular, and iliac veins in declining lesions that frequently contain cells with myxoid and order of frequency [29, 30, 60]. Tumor recurrence is not epithelioid changes. Genital leiomyomas are small, affected by tumor grade, size, or adjuvant therapy [16], painless lesions usually less than 2 cm in size that ap- the prognosis depending rather on location and surgi- pear in the areola of the nipple, scrotum, labia, penis, cal accessibility. and vulva. In 10% of cases, metastatic disease, usually in the lung or liver, is already present at the time of diagnosis [31]. Epitheloid or myxoid change and the presence of 18.2.1.2 Malignant Smooth Muscle Tumors granular eosinophilic cytoplasm cells in leiomyosarcomas are rare. These tumors are classified as epitheloid, Leiomyosarcomas account for between 5 and 10% of all myxoid, or granular cell leiomyosarcomas [22]. soft tissue tumors. They occur typically in adult life, although recently an association of Epstein Barr virus with leiomyosarcomas in young people with AIDS and 18.2.2 Tumors of Striated Muscle after organ transplantation has been reported by several groups [37, 40, 45]. 18.2.2.1 Benign Striated Muscle Tumors All leiomyosarcomas have the same histological characteristics. They are, however, divided into three differ- In general, benign soft tissue tumors are much more ent subgroups because of their clinical and biological frequent than their malignant counterparts. The oppo- differences [20]. site is true for striated muscle tumors, where benign Cutaneous and subcutaneous leiomyosarcomas must lesions account for no more than 2% of all striated mus- be differentiated. The smaller cutaneous lesions are ill- cle tumors. defined tumors with tumor strands blending in with the Adult rhabdomyoma is a hamartomatous process surrounding collagen and arrectores pilorum muscles. that is usually solitary and well defined or coarsely Patients present with cutaneous discoloration, umbili- lobulated. It shows a gray-yellow to red-brown color on cation, and ulceration. The subcutaneous lesions are macroscopic inspection and contains large, round well circumscribed and form a pseudocapsule. These polygonal cells intersected by fibrous strands [21]. grow faster and result only in skin elevation. It presents as a painless, round or polypoid mass in Cutaneous and subcutaneous leiomyosarcomas ac- the neck, which seems to arise from the branchial mus- count for 2–3% of all superficial soft tissue sarcomas. culature of the third and fourth clefts. Clinically it may They are most common in men in the fifth to seventh cause hoarseness or progressive difficulties in swallow- decades. Pain is a prominent feature in both tumors. As ing. Most cases occur in adults over 40 years old and these tumors are mostly solitary, multiplicity is always are solitary tumors. However, multifocality has been suggestive of metastasis from another site. Whereas described in about 20% but is restricted to the neck cutaneous leiomyosarcomas metastasize in 10% of cas- (Fig. 18.2). es, or less, subcutaneous lesions metastasize in 30–40% Fetal rhabdomyoma is a superficial tumor often with a of cases. They differ from the retroperitoneal leiomyo- mucoid glistening surface, usually polypoid or peduncu- sarcomas in their lack of regressive and degenerative lated and less than 5 cm in size.Both myxoid and cellular changes which is probably related to their smaller size. differentiated subtypes can be found. It is even rarer Leiomyosarcomas of the deep soft tissues are most than the adult subtype and occurs in the head and neck frequent in the retroperitoneum and in the abdominal regions of both children and adults. The median age is cavity. More than 60% of this subgroup occur in 4 years (3–58 years), with a 2.4:1 male predominance. women, usually after menopause. Symptoms are vague The classic fetal rhabdomyoma has a predilection for the and nonspecific. Less frequently, these tumors can be postauricular soft tissue. Some may be related to neuro- found in the deep soft tissues of the extremities, affect- muscular hamartoma (benign Triton tumor). ing both sexes equally. Genital rhabdomyomas form a group of polypoid or Vascular leiomyosarcomas are polypoid or nodular cauliflower-like masses covered by epithelium. These masses that are firmly attached to the vessel wall and tumors consist of centrally scattered muscle fibers and a spread along its surface.In veins the extension to the ad- matrix of collagen and mucoid material. They present 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 296

296 P.C.Seynaeve, P.J.L. De Visschere, L.L. Mortelmans, A.M. De Schepper

a b c

d e

Fig. 18.2Ia–f. Adult rhabdomyoma of the forearm in a 76-year-old man. a Axial spin-echo T1-weighted MR image. b Axial spin-echo T1-weighted MR image after gadolinium contrast injection. c Axial spin-echo proton density MR image. d Axial spin-echo T2-weighted MR image. e Axial spin-echo T2-weighted MR image with fat suppression. f Sagittal spin-echo T1-weighted MR image with fat suppression. MRI shows a round mass lesion between the superﬁcial and deep ﬂexor digitorum muscles. On T1-weighted MR images, the lesion is inhomogeneous and of higher signal intensity than adjacent normal muscle. There is a central focus of high signal intensity (a).After gadolinium contrast injection, a marked, inhomogeneous enhancement of the lesion is seen (b). High signal intensity is seen on both proton density and T2-weighted MR images (c, d). On T2-weighted MR image with fat suppression, the lesion remains hyperintense (e). On T1-weighted MR f image with fat suppression, fatty components can be excluded (f)

as slow-growing polypoid or cyst-like masses in the Institutes of Pathology, fewer than 15% of rhabdomyo- vagina or the vulva of young and middle-aged women. sarcomas occur in the extremities, with an equal distri- The median age is 42 years (range 30–48 years). A bution between upper and lower extremities [61]. similar lesion has been described in the prostate of a Histologically, this group contains several different 19-year-old male patient [21, 44]. types of tumors, depending on the cellularity. The WHO Rhabdomyomatous mesenchymal hamartomas are classification modifies slightly the previously accepted subcutaneous lesions composed of poorly oriented classification of Horn and Enterline (1958). The malig- skeletal muscle bundles blended with islands of fat, nant striated muscle tumors are subdivided in an em- fibrous tissue,and proliferated nerves.They occur in the bryonal, alveolar, and pleomorphic rhabdomyosarcoma orbital and periorbital regions of infants and young subgroup [28]. children. The embryonal group contains the spindle cell, botryoid, and anaplastic rhabdomyosarcoma subtypes. These subtypes range from poorly differentiated tumors that 18.2.2.2 Malignant Striated Muscle Tumors correspond histologically to the appearance of develop- ing muscle in an early gestational stage to well-differen- Rhabdomyosarcoma is frequent in persons under tiated tumors that resemble mature fetal muscle. Spin- 45 years of age. In children it is actually the most com- dle cell rhabdomyosarcoma is a subtype of this group of mon soft tissue tumor. According to the Armed Forces tumors and is characterized by the parallel orientation 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 297

Chapter 18 Tumors of Muscular Origin 297

Fig. 18.3Ia–f. Alveolar rhabdomyosarcoma of the left hypothenar in a 11-year- old girl, presenting with a painless swelling for 6 months. The volume of the swelling had increased during the last 2 weeks. a Axial spin-echo T1-weighted MR image. b Axial spin-echo T2-weighted MR image with fat suppression. c Coronal spin-echo T2-weighted MR image with fat suppression. d Axial spin-echo T1-weighted MR image after gadolinium contrast injection, dynamic sequence with subtraction images. e Axial spin-echo T1-weighted MR image after gadolinium contrast injection. f Sagittal spin-echo T1-weighted MR image after gadolinium contrast injection. The T1-weighted MR image demonstrates a large mass within the hypothenar muscles (abductor digiti minimi), inhomogeneous and slightly hyperintense to adjacent normal muscle. Infiltration is seen toward the muscle belly (a). On T2-weighted MR images with fat suppression, the lesion is ill-defined and of very high signal intensity. Presence of in homogeneity with a central scar-like component of low signal intensity (b). On coronal plane the lesion is fusiform (c). On dynamic T1-weighted MR sequences after gadolinium contrast injection, the lesion shows septal and central enhancement (d). On T1-weighted MR images, the lesion is inhomogeneous with nodular components of hyper- and hypointensity (e, f). A large, illdefined mass with inhomogeneous appearance on all MR sequences, f arising from the hypothenar in a child 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 298

298 P.C.Seynaeve, P.J.L. De Visschere, L.L. Mortelmans, A.M. De Schepper

a b

c d

Fig. 18.4Ia–d. Pleomorphic rhabdomyosarcoma of the right thigh presence of a central ﬂuid collection anterior to an area of low in a 63-year-old man. a Axial spin-echo T1-weighted MR image. signal intensity (b). There is no enhancement of both these areas b Axial spin-echo T2-weighted MR image. c Axial spin-echo after gadolinium contrast injection (c, d). A malignant tumor is T1-weighted MR image after gadolinium contrast injection. suggested by the inhomogeneous appearance in all sequences, d Sagittal spin-echo T1-weighted MR image after gadolinium con- location, and volume of the lesion. The pleomorphic subtype is trast injection. The T1-weighted MR image shows a rounded, well- characterized by areas of necrosis alternating with areas of circumscribed mass with mixed signal intensities (a). The mass is marked enhancement and areas of ring-like enhancement around even more inhomogeneous on T2-weighted MR image, with the low signal-intensity areas

of cells having some resemblance to leiomyosarcoma. seen in all subtypes, but in the anaplastic subtype dif- Recognition of this subtype is important because of its fuse anaplasia with the presence of clone-like clusters of good prognosis. anaplastic cells are predominant. Embryonal rhabdomyosarcoma accounts for 50–60% Alveolar rhabdomyosarcoma (solid and anaplastic) is of all rhabdomyosarcomas (3 million US children less composed of individual cellular aggregates that are sep- than 15 years of age).It principally affects children up to arated and surrounded by frameworks of dense, fibrous the age of 15 years and occurs mainly in the head and septa that contain dilated vascular channels. It is the neck region, the orbits, the genitourinary system, the second most frequent type and accounts for 20% of retroperitoneum, and the extremities. all malignant striated muscle tumors. Adolescents and Botryoid rhabdomyosarcoma is a variant with a poly- young adults between 10 and 25 years of age are most poid (grape-like) growth pattern and consists mainly frequently affected. It can be found in the same loca- of mucoid matrix with some sparse cells [46]. This tions as the embryonal rhabdomyosarcoma, although it myxoma-like tumor is often covered by hyperplastic or tends to occur more often as a deep-seated mass in the squama-like epithelium. It accounts for 5–10% of all extremities. Alveolar rhabdomyosarcomas has a worse rhabdomyosarcomas and occurs principally in mucosa- prognosis than other rhabdomyosarcomas (Fig. 18.3). lined hollow viscera such as the vagina and bladder. Pleomorphic rhabdomyosarcoma is histologically dif- The anaplastic rhabdomyosarcoma is histologically ficult to differentiate from other pleomorphic soft tissue defined by the presence of enlarged, atypical cells with tumors. It contains loosely arranged, larger pleomor- hyperchromatic nuclei. Focal anaplastic features can be phic cells. Cross-striations that are found in other sub- 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 299

Chapter 18 Tumors of Muscular Origin 299

types are rare in this group. It accounts for 5% of all of angiography is therefore limited nowadays. This cer- rhabdomyosarcomas and occurs mainly in patients tainly applies to tumors of muscular origin. over 40 years of age. Its predilection site is the thigh (Fig. 18.4). ࡯ Lymphangiography. Bipedal lymphography has been Clinically, rhabdomyosarcomas are rapidly growing described as useful only in detecting metastatic lesions masses which tend to cause pain and nerve compres- arising from muscular tumors in the lower trunk or in sion symptoms when they reach a large volume. These the lower extremities [4], but is today replaced by CT. tumors appear to involve bone more frequently than other soft tissue sarcomas, apart from synovial sarcoma. In a series published by Simmons and Tucker, bone 18.3.1.4 Scintigraphy invasion in association with the primary tumor was seen in more than 20% of cases. Remarkably only flat Both technetium and gallium were once proposed as bones were invaded. Bone destruction was permeative useful radiopharmaceuticals, the former for detecting and only exceptionally well defined. Sclerosis was an the presence and delineating the extent of a soft tissue unexpected finding in association with such an aggres- tumor, and the latter for demonstrating malignancy. sive tumor [52]. However, a lack of specificity was later established. The main role of scintigraphy lies in detecting skeletal metastases [34, 51, 53, 55]. 18.3 Imaging

18.3.1 Imaging Studies Other Than MRI 18.3.1.5 Computed Tomography

18.3.1.1 Plain Radiography Before the advent of MRI, CT was the only imaging modality able to evaluate soft tissue tumor extent and Although plain radiography cannot be expected to pro- medullary involvement [3, 35]. Its role is now restricted vide specific information about the nature of a soft tis- to the detection of calcifications, bone involvement, and sue lesion, it remains useful to start the evaluation of intratumoral gas [48, 63]. any soft tissue tumor with plain radiographs [6, 29]. In a series of 14 tumors reported on by McLeod, Apart from giving some idea about the size and location leiomyosarcomas were usually large, with frequent of the mass, this reveals the presence of calcifications necrotic or cystic changes. Calcifications were not seen. within the lesion and shows any coexisting bone in- Necrotic metastases were observed in several cases [41]. volvement [34, 50]. For best results, a low-kilovoltage Although the CT appearance remains nonspecific, the technique should be used to provide maximum density presence of necrotic metastases can be suggestive of the differentiation between tissues [9, 46]. diagnosis. In a series of 73 tumors of the thigh by Rich, there were only 4 rhabdomyosarcomas; in all 4 of these cases, 18.3.1.2 Ultrasound the presence of asymmetrical thickening was noted on CT scans [52]. Ultrasound, as a cheap and readily available technique, is of use in the general workup of soft tissue masses pro- viding information about size and internal characteris- 18.3.2 MRI Findings tics [5, 57, 68, 69]. Its main use for establishing a precise diagnosis The value of MRI in grading and characterization of lies in guiding percutaneous biopsy [3, 10, 33]. Color soft tissue tumors has been the subject of a large num- Doppler techniques are useful in assessing vascular- ber of publications, some of them controversial [1, 2, ity but offer no help in the diagnosis of muscular 6–8, 11–15, 23, 33, 39, 43, 47, 56, 58, 62–67], and has been tumors. largely dealt with in Chap. 11. In the uterus, leiomyomas appear as sharply mar- ginated,homogeneous areas of lower signal intensity on 18.3.1.3 Angiography T2-weighted images than the surrounding myometrium; inhomogeneity is indicative for complicated or vas- ࡯ Angiography. Both conventional cut-film and digital cular fibroids [54]. This does not seem to be the case in subtraction angiography can be used for preoperative other locations. In the bladder three leiomyomas pre- vascular mapping and to establish access for intra-arte- senting as an inhomogeneous mass with overall high rial chemotherapy [17, 34]. Angiographic findings in signal and dot-like foci of low signal on T2-weighted soft tissue tumors are entirely nonspecific, and the use images have been published [42]. 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 300

300 P.C.Seynaeve, P.J.L. De Visschere, L.L. Mortelmans, A.M. De Schepper

Fig. 18.5Ia–f. Leiomyoma of the flexor compartment of the right arm in a 56-year-old woman. a Ultrasound, axial plane. b Plain CT. c CT scan after iodinated contrast injection. d Axial spin-echo T1- weighted MR image. e Axial spin-echo T2-weighted MR image. f Axial spin-echo T1-weighted MR image after gadolinium contrast injection. Ultrasound shows a well-circumscribed, oval and slightly hypoechoic mass within the biceps muscle (a). The lesion is of low attenuation on plain CT (b) and is enhanced peripherally after contrast injection (c). On MRI the well-defined lesion is hyperintense to muscle on T1-weighted MR images (d) and shows an inhomogeneous, stippled high signal on T2-weighted images (e), and an inhomogeneous enhancement after gadolinium contrast injection (f). Nonspecific MR findings of a well-circumscribed, benign intramuscular tumor

b c

d e f 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 301

Chapter 18 Tumors of Muscular Origin 301

Fig. 18.7Ia,b. Leiomyosarcoma of the thigh in a 88-year-old woman. a Sagittal spin-echo T1-weighted MR image. b Sagittal c spin-echo T1-weighted MR image after gadolinium contrast injection.MRI shows a large and lobulated mass displacing the adjacent muscles. On T1-weighted images the lesion is iso- to hyperintense Fig. 18.6Ia–c. Low-grade leiomyosarcoma of the vastus inter- (a). After gadolinium contrast injection, a thick and irregular rim medius muscle in a 33-year-old man presenting with pain and enhancement is seen surrounding areas of central necrosis (b). swelling of the left thigh.a Coronal spin-echo T1-weighted MR im- Inhomogeneity of a mass on T1-weighted images and peripheral age. b Coronal spin-echo T1-weighted MR image after gadolinium enhancement are in favor of a malignant tumor contrast injection. c Axial spin-echo T2-weighted MR image. Pres- ence of a fusiform soft tissue mass deep in the left thigh hyperintense relative to adjacent normal muscle on T1-weighted images (a). After gadolinium contrast injection, there is marked enhancement of the lesion (b). On T2-weighted images, the lesion is inhomogeneous and of high signal intensity (c). There are numerous feeding vessels indicating a highly vascular lesion.Although the lesion exhibits imaging features similar to those of an alveolar soft tissue sarcoma (Fig. 23.19–23.21), histological diagnosis revealed a low-grade leiomyosarcoma illustrating the difﬁculty in MR pattern recognition versus histological diagnosis

In our series of 26 muscular tumors, only one lesion a more speciﬁc diagnosis [62]. In our own series, proved to be a leiomyoma. It was found in the deep soft leiomyosarcomas mostly appeared as large masses with tissues of the upper arm (Fig. 18.5). central necrosis and a peripheral rim-like enhancement Leiomyosarcomas mostly present with aspeciﬁc MR after gadolinium contrast administration (Fig. 18.7). features, i.e., spindle-shaped masses with a long T1 and Bone involvement is seen in 10% of cases (Figs. 18.8, a long T2 relaxation time (Fig. 18.6). Overall low signal 18.9) [25, 26]. intensity or low signal intensity components allow 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 302

302 P.C.Seynaeve, P.J.L. De Visschere, L.L. Mortelmans, A.M. De Schepper

Fig. 18.8Ia–d. Leiomyosarcoma of the right arm in a 36-year-old woman. a Coronal spin-echo T1-weighted MR image. b Axial spin-echo T1-weighted MR image. c Axial T2-weighted MR image. d Axial spin-echo T1-weighted MR image after gadolinium contrast injection. A spindle-shaped mass is seen, lying along the long axis of the limb and invading the humerus (a). The lesion is inhomogeneous and of intermediate signal intensity on the T1-weighted MR images (a, b). The tissue inhomogeneity is accentu- b ated on the T2-weighted MR image, which shows mixed signal intensities (c). After gadolinium contrast injection, there is inhomogeneous enhancement (d). An aggressive muscle tumor with bone involvement

a d

In cases of vascular leiomyosarcomas, differential di- Recent advances in MRI technology allow higher-res- agnosis with thrombus is rather straightforward, since olution imaging in shorter acquisition times but no sig- tumor expands the vessel to a diameter several times nificant progress is seen regarding tissue diagnosis [24]. the original, while thrombus never expands the diame- Dynamic contrast-enhanced MRI (parametric imaging) ter to more than twice the original one. In thrombosis may help in: (1) defining areas of tumor viability prior T1 and T2 is generally increased, with a clear delin- to biopsy, (2) determining response to chemotherapy, eation of the vessel wall [59]. and (3) evaluating tumor recurrence following surgery One case of a myxoid leiomyosarcoma showed high [68]. signal intensity on T2-weighted images and a marked enhancement after gadolinium contrast injection, more Things to remember: pronounced at the center of the lesion (Fig. 18.10). 1. Smooth vessel tumors have no specific imaging Rhabdomyosarcomas also have rather nonspecific features except for vascular leiomyosarcoma, MR features, and they are seldom located in the extrem- which mostly occurs within the inferior vena cava. ities. Embryonal rhabdomyosarcomas show a more 2. Benign striated muscle tumors are extremely rare. homogeneous low signal intensity on both T1- and T2- 3. Rhabdomyosarcoma is the most common soft tis- weighted images and no obvious intratumoral necrosis sue tumor in children, the embryonal subtype (Figs. 18.11, 18.12). being by far the most frequent. Embryonal subtypes can cause bowing of tubular 4. Leiomyosarcoma mostly present as large, spindle- bones in children, falsely mimicking a slowly growing shaped masses with variable signal intensities, tumoral process [62]. Alveolar rhabdomyosarcomas are central necrosis,and peripheral contrast enhance- characterized by multiple areas of tumoral necrosis ment. (Figs. 18.12, 18.13, 18.14), while pleomorphic rhabdomyosarcomas have areas of necrosis alternating with areas of marked ring-like enhancement around areas of low signal intensity (Figs. 18.15). 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 303

Chapter 18 Tumors of Muscular Origin 303

Fig. 18.9Ia–e Leiomyosarcoma of the right thigh in a 26-year-old woman. a Plain radiograph. b Plain CT. c Axial spin-echo T2- weighted MR image. d Coronal spin-echo T1-weighted MR image. e Coronal spin-echo T1-weighted MR image after gadolinium contrast injection. Plain radiography demonstrates an indistinct soft tissue swelling with extensive mottled bone involvement and a pathological fracture of the femoral neck (a). CT conﬁrms these areas of bone erosion and patchy sclerosis (b). The soft tissue mass surrounds the hip and extends toward the midline. It presents as a very hyperintense mass on T2-weighted MR image (c), while the T1-weighted MR image shows an inﬁltrating tumor (d) with essen- tially peripheral enhancement after gadolinium contrast injection e (e).Aggressive muscle tumor with extracompartmental (bone and subcutis) extension 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 304

304 P.C.Seynaeve, P.J.L. De Visschere, L.L. Mortelmans, A.M. De Schepper

Fig. 18.10Ia–c. Myxoid leiomyosarcoma of the anterior left thigh in a 63-year-old woman. a Axial spin-echo T1-weighted MR image. b Axial spin-echo T2-weighted MR image. c Axial spin-echo T1-weighted image after gadolinium contrast injection. MR shows a lobulated mass that is isointense to muscle on T1-weighted MR image (a) with mixed but mainly high signal intensity on the T2-weighted MR image (b) and inhomogeneous enhancement after gadolinium contrast injection (c). Contrast enhancement seems to decrease from the center to the periphery of the mass. Nonspeciﬁc mass with overwhelming myxoid components 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 305

Chapter 18 Tumors of Muscular Origin 305

Fig. 18.11Ia–e. Embryonal rhabdomyosarcoma of the left buttock in a 22-month-old boy. a Axial spin-echo T1-weighted MR image. b Axial spin-echo T2-weighted MR image. c Axial spin-echo T1- weighted MR image after gadolinium contrast injection. d Coronal spin-echo T1-weighted MR image (2 months later). e Coronal spin-echo T1-weighted MR image after gadolinium contrast injection (at the same time as d). On T1-weighted MR image, the lesion demonstrates a hypo- to isointensity compared with the adjacent muscle (a), while there is high signal on T2-weighted MR image with some internal strands of low signal intensity (b). After gadolinium contrast injection, there is evident enhancement of some parts of the tumor, but large areas do not enhance at all (c). No necrosis is seen. Comparable signal patterns are seen on a follow-up MRI study with a plain T1-weighted MR image (d) and a T1-weighted MR image after gadolinium contrast injection (e). A large tumor with malignant imaging ﬁndings arising from a gluteal muscle in a young child without distinct areas of necrosis. e This embryonal subtype of rhabdomyosarcoma shows a marked, slightly inhomogeneous enhancement without extensive necrosis 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 306

306 P.C.Seynaeve, P.J.L. De Visschere, L.L. Mortelmans, A.M. De Schepper

ab a

b d

Fig. 18.12Ia,b. Embryonal rhabdomyosarcoma of the tongue in a Fig. 18.13Ia–d. Alveolar rhabdomyosarcoma of the right thigh in a 15-year-old boy, 14 years after treatment for a rhabdomyosarcoma 71-year-old woman. a Sagittal spin-echo T1-weighted MR image. at the same location. a Axial spin-echo T1-weighted MR image. b Sagittal spin-echo T1-weighted MR image after gadolinium con- b Axial spin-echo T1-weighted MR image after gadolinium contrast injection. c Axial spin-echo T2-weighted MR image. d Axial trast injection. Huge mass at the tongue base, hardly to differenti- spin-echo T1-weighted MR image after gadolinium contrast injec- ate from the intrinsic tongue musculature on a T1-weighted MR tion.A voluminous mass with very inhomogeneous signal character- image (a). After gadolinium contrast injection, there is marked istics is seen on T1-weighted MR images. There are hypointense inhomogeneous enhancement of the lesion (b) areas suggestive of central necrosis (a). After gadolinium contrast injection, only peripheral enhancement is seen (b, d). Higher signal intensity is seen on proton density and T2-weighted MR images especially in the necrotic areas (c).Location,large size,inhomogeneous signal intensity on T1-weighted MR images, high signal intensity on T2-weighted MR images, and mostly peripheral enhancement after gadolinium injection are in favor of a malignant muscular tumor. The alveolar subtype is characterized by multiple areas of necrosis 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 307

Chapter 18 Tumors of Muscular Origin 307

b c

Fig. 18.14Ia–c. Alveolar rhabdomyosarcoma of the upper arm in a contrast injection (b). On sagittal plane the lesion has a fusiform 50-year-old man. a Axial T1-weighted MR image. b, c Axial (b) and shape with ill-deﬁned margins proximally and distally (c). Histo- sagittal (c) T1-weighted MR image after gadolinium contrast in- logical examination after biopsy and resection revealed an alveo- jection. Collar button-shaped mass within the triceps muscle of lar rhabdomyosarcoma. This case illustrates the variable morphol- the upper arm, hyperintense to adjacent normal muscle on T1- ogy and signal-intensity characteristics of rhabdomyosarcomas weighted MR images (a) and strongly enhancing after gadolinium 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 308

308 P.C.Seynaeve, P.J.L. De Visschere, L.L. Mortelmans, A.M. De Schepper

Fig. 18.15Ia–f. Rhabdomyosarcoma of the adductor region of the necrosis (b). Arteriography reveals the presence of neovascularity right thigh in a 78-year-old woman. a Plain CT. b CT after iodinat- and of a tumoral blush (c). On MR images there is a mass with ed contrast injection. c Arteriography with direct retrograde multiple central hypointensities on T1-weighted MR images (d), femoral artery injection. d Coronal spin-echo T1-weighted MR which become hyperintense on T2-weighted MR images (e). After image. e Axial spin-echo T2-weighted MR image. f Coronal spin- gadolinium contrast injection, strong enhancement at the periph- echo T1-weighted MR image after gadolinium contrast injection. ery is seen around the intralesional necrotic areas (f). This case of CT shows a large and lobulated soft tissue mass with central hypo- a highly malignant tumor presents with large areas of intratu- densities (a). There is a marked enhancement after iodinated con- moral necrosis and neovascularity on angiography trast injection: rim-like enhancement is seen surrounding areas of 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 309

Chapter 18 Tumors of Muscular Origin 309

References 25. Geussens E, Vanhoenacker P, Brijs S, Van Aelst F (1995) Leio- myosarcoma. J Belge Radiol 78:228–229 26. Hartman DS, Hayes WS, Choyke PL, Tibbets GP (1992) 1. Armstrong SJ, Wakeley CJ, Goddard PR, Watt I (1992) Review Leiomyosarcoma of the retroperitoneum and inferior vena ca- of the use of MR imaging in soft tissue lesions. Clin Radiol va: radiologic-pathologic correlation. Radiographics 12:1203– 46:311–317 1220 2. Beltran J (1990) MRI musculoskeletal system. Lippincott, 27. Herlin K, Willén H, Rydholm A (1990) Deep seated soft tissue Philadelphia, pp 10.4–10.5 leiomyomas. Report of four cases. Skeletal Radiol 19:363–365 3. Berger PE, Kuhn JP (1978) Computed tomography of tumors 28. Horn RC, Enterline HT (1958) Rhabdomyosarcoma: a clinico- of the musculoskeletal system in children. Radiology 127: pathological study of 29 cases. Cancer 11:181 171–175 29. Kevorkian J, Cento DP (1973) Leiomyosarcoma of large arter- 4. Bergiron C, Markovits P, Benjafaar M, Piekarski JD, Garel L ies and veins. Surgery 73:390–400 (1979) Lymphography in childhood rhabdomyosarcomas. 30. Killoran TP, Wells WA, Barth RJ, Goodwin DW (2003) Leio- Radiology 133:627–630 myosarcoma of the popliteal vein. Skeletal Radiol 32(3):174– 5. Bernardino ME, Jing BS, Thomas JL, Lindell MM Jr, Zornoza JI 178 (1981) The extremity soft-tissue lesions: a comparative study 31. Kransdorf MJ (1995) Malignant soft tissue tumors in a large of ultrasound, computed tomography and xeroradiography. referral population distribution of specific diagnoses by age, Radiology 139:53–59 sex and location. AJR Am J Roentgenol 164:129–134 6. Berquist TH (1990) MRI of the musculoskeletal system, 2nd 32. Kransdorf MJ (1995) Benign soft tissue tumors in a large refer- edn. Raven, New York, pp 447–458 ral population distribution of specific diagnoses by age, sex 7. Bloem JL (1992) Imaging of soft tissue tumors. J Belge Radiol and location. AJR Am J Roentgenol 164:395–402 75:265–273 33. Kransdorf MJ, Jelinek JS, Moser RP Jr, Utz JA, Brower AC, Hud- 8. Bondetti PR, Ehman RL (1992) Soft tissue sarcomas: use of son TM, Berrey BH (1989) Soft tissue masses: diagnosis using textural patterns in skeletal muscle as a diagnostic feature in MR imaging. AJR Am J Roentgenol 153:541–547 postoperative MR imaging. Radiology 183:845–848 34. Kransdorf MJ, Jelinek JS, Moser RP (1993) Imaging of soft tis- 9. Cavanagh RC (1973) Tumors of the soft tissues. Semin Roent- sue tumors. Radiol Clin North Am 31:359–372 genol 8:73–89 35. Lateur L, Ramon F (1992) CT of soft tissue tumors. J Belge Ra- 10. Christensen RA, Van Sonnenberg E, Casola G, Wittich GR diol 75:281–285 (1988) Ultrasound in the musculoskeletal system. Radiol Clin 36. Ledesma-Medina J, Oh KS, Girdany BR (1980) Calcification in North Am 26:145–156 childhood leiomyoma. Radiology 135:339–341 11. Crim JR, Seeger LL, Yao L, Chandnani V (1992) Diagnosis of 37. Lee ES, Locker J, Nalesnik M, Reyes J, Jaffe R, Alashari M, Nour soft tissue masses with MR imaging: can benign masses be dif- B, Tzakis A, Dickman PS (1995) The association of Epstein ferentiated from malignant ones? Radiology 185:581–586 Barr virus with smooth muscle tumors occurring after organ 12. Daldrup H, Shames DM, Wendland M, Okuhata Y, Link TM, transplantation. N Engl J Med 332:19–25 Rosenau W,Lu Y,Brash RC (1998) Correlation of dynamic con- 38. Lubbers PR, Chandra R, Markle BM, Downey EF Jr, Malawer M trast-enhanced magnetic resonance imaging with histologic (1987) Calcified leiomyoma of the soft tissues of the right but- tumor grade: comparison of macromolecular and small mole- tock (case report 421). Skeletal Radiol 16:252–256 cular contrast media. Pediatr Radiol 28:67–78 39. Ma LD, Frassica FJ, Scott WW, Fishman EK, Zerhouni EA 13. De Schepper AM, Ramon FA,Degryse HR (1992) Magnetic res- (1995) Differentiation of benign and malignant musculoskele- onance imaging of soft tissue tumors. J Belge Radiol 75:286– tal tumors: potential pitfalls with MR imaging. Radiographics 296 15:349–366 14. De Schepper AM, Ramon F,De Beuckeleer L (1995) MRI of soft 40. McClain KL, Leach CT,Jenson HB, Joshi VV,Pollock BH, Parm- tissue tumors. In: Baert AL, Grenier P,Willi UV (eds) Syllabus ley RT, Di Carlo FJ, Chadwick EG, Murphy SB (1995) Associa- categorical course ECR 95, musculoskeletal imaging: an up- tion of Epstein Barr virus with leiomyosarcomas in young date. Springer, Berlin Heidelberg New York, pp 155–164 people with AIDS. N Engl J Med 332:12–18 15. Devos V,De Schepper A, Degryse H, Ramon F (1992) Diagnos- 41. McLeod AJ, Zornoza J, Chirkhoda A (1984) Leiomyosarcoma: tic imaging of muscular tumors. J Belge Radiol 75:327–334 computed tomography findings. Radiology 152:133–136 16. Dzsinich C, Gloviczki P, Van Heerden JA (1992) Primary ve- 42. Menahem MM, Slywotsky C (1992) Urinary bladder leio- nous leiomyosarcoma: a rare but lethal disease. J Vasc Surg myoma: MRI findings. Urol Radiol 14:197–199 15:595–603 43. Mirowitz SA, Totty WG, Lee JKT (1992) Characterization of 17. Ekelund L, Rydholm A (1983) The value of angiography in soft musculoskeletal masses using dynamic Gd DTPA enhanced tissue leiomyosarcomas of the extremities. Skeletal Radiol spin echo MRI. J Comput Assist Tomogr 16:120–125 9:201–204 44. Morra MN, Manson AJ, Gavrel GJ (1992) Rhabdomyoma of the 18. Enzinger FM, Weiss SW (1995) Radiologic evaluation of soft prostate. Urology 39:271–273 tissue tumors. In: Enzinger MM, Weiss SW (eds) Soft tissue 45. Mueller BV, Butler KM, Higham MC, Husson RN, Montrella tumors, 3rd edn. Mosby, St Louis, pp 7–8 KA, Pizzo PA (1994) Smooth muscle tumors in children with 19. Enzinger MM, Weiss SW (1995) Benign tumors of smooth HIV.Pediatrics 90:460–463 muscle. In: Enzinger MM, Weiss SW (eds) Soft tissue tumors, 46. Nelson GL, Staple TW, Ewans RG (1973) Soft tissue radio- 3rd edn. Mosby, St Louis, pp 467–490 graphic techniques. Semin Roentgenol 8:19–24 20. Enzinger MM,Weiss SW (1995) Leiomyosarcoma. In: Enzinger 47. Olson PN, Everson LI, Griffiths HJ (1994) Staging of muscu- MM, Weiss SW (eds) Soft tissue tumors, 3rd edn. Mosby, loskeletal tumors. Radiol Clin North Am 32:151–162 St Louis, pp 491–510 48. Petrasnick JP, Turner DA, Charters JR, Gitelis S, Zacharias CE 21. Enzinger MM, Weiss SW (1995) Rhabdomyoma. In: Enzinger (1986) Soft tissue masses of the locomotor system. Radiology MM, Weiss SW (eds) Soft tissue tumors, 3rd edn. Mosby, 160:125–133 St Louis, pp 523–538 49. Petterson H, Gillespy T III, Hamlin DJ, Enneking WF, Spring- 22. Enzinger MM, Weiss SW (1995) Rhabdomyosarcoma. In: En- field DS, Andrew ER, Spanier S, Slone R (1987) Primary mus- zinger MM,Weiss SW (eds) Soft tissue tumors, 3rd edn. Mosby, culoskeletal tumors: examination with MR imaging compared St Louis, pp 539–578 with conventional modalities. Radiology 164:237–241 23. Fletcher BG, Hanna SL, Fairclough DL, Gronemeyer SA (1992) 50. Petterson H, Springfield DS, Enneking WF (1987) Radiologic Pediatric musculoskeletal tumors: use of dynamic, contrast management of musculoskeletal tumors. Springer, Berlin Hei- enhanced MR imaging to monitor response to chemotherapy. delberg, pp 19–38 Radiology 184:243–248 51. Resnick D, Niwayama G (1995) Soft tissues. In: Resnick D, 24. Fujimoto H, Murakami K, Ichikawa T, Matsubara T, Tsumurai Niwayama G (eds) Diagnosis of bone and joint disorders, 3rd Y,Masuda S,Terauchi M,Ozawa K,Nosaka K,Arizimu N (1993) edn. Saunders, Philadelphia, pp 4491–4622 MRI of soft tissue lesions: opposed phase T2* weighted gradi- ent echo images. J Comput Assist Tomogr 17:418–424 18_DeSchepper_tumors_of 15.09.2005 13:29 Uhr Seite 310

310 P.C.Seynaeve, P.J.L. De Visschere, L.L. Mortelmans, A.M. De Schepper

52. Rich PJ, King W III (1982) Benign cortical hyperostosis under- 61. Stout AP, Lattes R (1966) Tumors of the soft tissues. (Atlas of lying soft tissue tumors of the thigh. AJR Am J Roentgenol tumor pathology) American Forces Institute of Pathology, 138:419–422 Washington DC 53. Schwartz HS, Jones CK (1992) The efﬁcacy of gallium scintig- 62. Sundaram M, McLeod RA (1990) MR Imaging of tumor and raphy in detecting malignant soft tissue neoplasms. Ann Surg tumor like lesions of the bone and soft tissue. AJR Am J 215:78–82 Roentgenol 155:817–824 54. Scoutt LM, McCarthy SM (1992) Female pelvis. In: Stark DD, 63. Suzuki Y, Ehara S, Shiraishi H, Nishida J, Murooka G, Bradley WG Jr (eds) Magnetic resonance imaging, 2nd edn. Tamakawa Y (1997) Embryonal rhabdomyosarcoma of foot Mosby-Yearbook, St Louis, pp 1958–1963 with expansive growth between metatarsals. Skeletal Radiol 55. Shapeero LG, Couanet D, Vanel D, Ackerman LV, Terrier La- 26:128–130 combe MJ, Flamant F, Contesso G, Lumbroso J (1993) Bone 64. Totty WG, Murphy WA,Lee JKT (1986) Soft tissue tumors: MR metastases as the presenting manifestation of rhabdomyosar- imaging. Radiology 160:135–141 coma in childhood. Skeletal Radiol 22:433–438 65. Vanel D, Lacombe MJ, Couanet D, Kalifa C, Spielmann M, 56. Shinkwin MA, Lenkinski RE, Daly JM, Zlatin MB, Frank TS, Genin J (1987) Musculoskeletal tumors: follow-up with MR Holland GA, Kressel HY (1991) Integrated magnetic resonance imaging after treatment with surgery and radiotherapy. imaging and phosphorus spectroscopy of soft tissue tumors. Radiology 164:243–245 Cancer 67:1849–1858 66. Vanel D, Shapeero LG, Gilles R, Genin J, Contesso G (1992) 57. Simmons M, Tucker AK (1978) The radiology of bone changes Imaging in the follow-up of soft tissue tumors. J Belge Radiol in rhabdomyosarcoma. Clin Radiol 29:47–52 75:274–275 58. Sintzoff SA Jr, Gillard I,Van Gansbeke D, Gevenois PA, Salmon 67. Vanel D, Shapeero LG, De Baere T, Gilles R, Tardivon A, Genin I, Struyven J (1992) Ultrasound evaluation of soft tissue tu- J, Guinebretière JM (1994) MR imaging in the follow up of ma- mors. J Belge Radiol 75:276–280 lignant and aggressive soft tissue tumors: results of 511 exam- 59. Sostman HD, Prescott DM, Dewhirts MW, Dodge RK, Thrall inations. Radiology 190:263–268 DE, Page RL, Tucker JA, Harrelson JM, Reece G, Leopold KA, 68. Verstraete KL, De Deene Y, Roels H, Dierick A, Uyttendaele D, Olesson JR, Charles HC (1994) MR Imaging and spectroscopy Kunnen MC (1994) Benign and malignant musculoskeletal le- for prognostic evaluation in soft tissue sarcomas. Radiology sions: dynamic contrast enhanced MR imaging – parametric 190:269–275 “ﬁrst-pass” images depict tissue vascularisation and perfu- 60. Stellard D, Sundaram M, Johnson FE, Janney C (1992) sion. Radiology 192:835–843 Leiomyosarcoma of great saphenous vein (case report 747). 69. Vincent LM (1988) Ultrasound of soft tissue abnormalities of Skeletal Radiol 21:399–401 the extremities. Radiol Clin North Am 26:131–144