280 Primary Tumors of the Spine Sebnem Orguc, MD1 Remide Arkun, MD1 1 Department of Radiology, Celal Bayar University, Manisa, Türkiye Address for correspondence Sebnem Orguc, MD, Department of 2 Department of Radiology, Ege University, İzmir, Türkiye Radiology, Celal Bayar University, Manisa, Türkiye (e-mail: [email protected]; [email protected]). Semin Musculoskelet Radiol 2014;18:280–299. Abstract Spinal tumors consist of a large spectrum of various histologic entities. Multiple spinal lesions frequently represent known metastatic disease or lymphoproliferative disease. In solitary lesions primary neoplasms of the spine should be considered. Primary spinal tumors may arise from the spinal cord, the surrounding leptomeninges, or the extradural soft tissues and bony structures. A wide variety of benign neoplasms can involve the spine including enostosis, osteoid osteoma, osteoblastoma, aneurysmal bone cyst, giant cell tumor, and osteochondroma. Common malignant primary neo- plasms are chordoma, chondrosarcoma, Ewing sarcoma or primitive neuroectodermal Keywords tumor, and osteosarcoma. Although plain radiographs may be useful to characterize ► spinal tumor some spinal lesions, magnetic resonance imaging is indispensable to determine the ► extradural tumor extension and the relationship with the spinal canal and nerve roots, and thus determine ► magnetic resonance the plan of management. In this article we review the characteristic imaging features of imaging extradural spinal lesions. Spinal tumors consist of a large spectrum of various histo- Benign Tumors of the Osseous Spine logic entities. Primary spinal tumors may arise from the spinal cord (intraaxial or intramedullary space), the sur- Enostosis rounding leptomeninges (intradural extramedullary space), Enostosis, also called a bone island, is a frequent benign or the extradural soft tissues and bony structures (extra- hamartomatous osseous spinal lesion with a developmental dural space). Almost 60% of the spinal tumors are located in origin.3 It is frequently located between T1 and T7 in the the extradural space, whereas 40% are located within the thoracic spine and between L2 and L3 in the lumbar spine. It is dural sac. Primary tumors of the spine are uncommon and composed of cortical bone with irregular margins merging represent < 5% of all bone neoplasms as compared with with the medullary bone, commonly adjacent to the endos- secondary metastatic disease, multiple myeloma, and teal surface. The spiculated or thornlike lesions are typically lymphoma.1 round or oval with a size up to 2 cm in diameter. On magnetic Clinical signs and symptoms of spinal tumors are variable resonance imaging (MRI) enostoses demonstrate low signal and nonspecific. Most common symptom is pain, which is on both T1-weighted images and T2-weighted images parallel present in 85% of patients with primary spinal tumors.2 Other to cortical bone. The surrounding trabecular bone displays symptoms include back pain, weakness, radicular pain, and normal signal (►Fig. 1). Intraosseous vacuum phenomena This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. paresthesia, which may often be attributed to degenerative may mimic a focus of enostosis with low signal on all disease. Together with the relatively low incidence of spinal sequences; however, it usually exhibits well-defined margins tumors in comparison with degenerative processes, a delayed (►Fig. 2). These features allow differentiation of these lesions diagnosis is quite common. from other sclerotic spine lesions including osteoblastic Imaging features of the primary spinal lesions are often metastases, osteoid osteoma, and low-grade osteosarcoma characteristic, and the various available imaging modalities in the vast majority of cases, avoid unnecessary evaluation, provide useful tools for narrowing the differential diagnosis and obviate the need for biopsy. However, biopsy may be and for planning further clinical treatment (►Table 1). considered if there is an increase in size. Enostosis is a Issue Theme Spine; Guest Editor, Mara Copyright © 2014 by Thieme Medical DOI http://dx.doi.org/ Epermane, MD Publishers, Inc., 333 Seventh Avenue, 10.1055/s-0034-1375570. New York, NY 10001, USA. ISSN 1089-7860. Tel: +1(212) 584-4662. Table 1 Features of primary osseous spinal lesions Age Locationa Characteristic MRI featuresb Key facts Gender features % spinal involvement vs other anatomical locations à à Enostosis Any, M ¼ FAdjacenttoendos-Spiculated margins, T1, T2,noCE Nopain teal surface of Surrounding trabec- Any bone may be cortex ular bone normal involved à Ãà Osteoid osteoma 10–20 y, M/F ¼ 2–3/1 Posterior elements Radiolucent T1, T2, diffuse, Pain worsens at 10% in spine (75%) nidus < 2cm,sur- marked CE night and is relieved L > C > T > S rounding sclerosis/ by salicylates edema à Ãà à Ãà Osteoblastoma 10–30 y Posterior elements Expansile, lytic, , T1, , T2, Pain is nonspecific M/F ¼ 2–2.5: 1 (85%), extend to multifocal minerali- diffusevariableCE Osteolytic 30–40% in spine vertebral body zation, secondary lesion > 2cmwith C > T ¼ L ¼ S ABC ascleroticring;may be aggressive Ãà Ãà ÃÃà Aneurysmal <20 y (%60) Posterior element, Expansile, thin- T1, , T2, Back pain is most à bone cyst F > M 70–90% extend to walled cavities with Peripheral, septal severe at night; 12–30% in spine vertebral body fluid–fluid levels CE pathologic frac- T > L, C > S tures may occur Ãà à Ãà Giant cell tumor 20–40 y (80%) Sacrum, vertebral Expansile, second- T1, , T2, Ãà Rare before skeletal maturity body ary ABC Diffuse CE M/F ¼ 1:2.5 in spine 7–15% in spine ÃÃà ÃÃà Hemangioma Any age Vertebral body > T1, T2, Well-circumscribed May extend epidur- Primary Tumors of the Spine M ¼ F posterior element Fallows fat signal lesion with coarse ally and cause Ãà Seminars in Musculoskeletal Radiology Vol. 18 No. 3/2014 Aggressive type F > M Diffuse CE vertical trabeculae vertebral fracture or CT: white polka dots cord compression Osteochondroma 20–40 y Spinous transverse Follows vertebral Sessile or pedicu- “Cauliflower” M/F ¼ 3/1 process > vertebral body lated, marrow con- lesion; spinal cord < 5% spine body tinuity, cartilage compression is rare 1–4% in solitary C (50%, predilection cap 7–9% in multiple form of C2) > T > L > S à Ãà ÃÃà Chordoma 30–60 y Arising from no- , T1, T2 (higher Destructive midline Histology: physali- M/F ¼ 2:1 tochordal remnants than disk) mass with multiple phorous cells, Sacral location: no Sacrococcygeal Septal, peripheral septa, calcification, distant metastases gender predilection (50%) > sphenooc- CE soft tissue mass are uncommon, but cipital (35%) > secondary sites may Orguc, Arkun vertebral body be involved (15%) (Continued) 281 This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. 282 Seminars in Musculoskeletal Radiology Vol. 18 No. 3/2014 Primary Tumors of the Spine Table 1 (Continued) Age Locationa Characteristic MRI featuresb Key facts Gender features % spinal involvement vs other anatomical locations à ÃÃà Chondrosarcoma 40–50 y Thoracic spine T1, T2 Lytic, destructive Malignant degener- ÃÃà M/F ¼ 2:1 Septal, peripheral mass with or with- ation of osteochon- 3–12% spine CE out chondroid ma- droma or trix (rings and arcs enchondroma is of calcification) possible à à Orguc, Arkun Osteosarcoma 30 y Posterior elements T1, T2, Aggressive, perme- May be associated Ãà M/F ¼ 1 79% Diffuse CE ative, destructive with Paget disease 0.6–3.2% spine and sacrum Involving adjacent lesion-forming im- and previous radia- vertebra 17% mature bone and tion therapy, high Spinal canal inva- soft tissue mass levels of alkaline sion 84% phosphatase, pul- monary metastases common, pneumo- thorax may occur Ãà Ãà ÃÃà Ewing sarcoma/PNET 10–30 y Sacrum > spine T1, , T2 Permeative, lytic le- Localized pain; an Ãà M/F ¼ 2:1 Vertebral body þ Diffuse CE sion with soft tissue elevated erythro- 3–10% spine posterior elements mass cyte sedimentation rate may simulate osteomyelitis à Ãà ÃÃà Langerhans < 20 y Vertebral body , T1, T2 Vertebra plana Ãà cell histiocytosis 6% in spine T > L, C Diffuse CE Intact end plates ABC, aneurysmal bone cyst; CT, computed tomography; M/F, male-to-female ratio; MRI, magnetic resonance imaging; PNET, primitive neuroectodermal tumor. aC, cervical; T, thoracic; L, lumbar; S, sacral. à Ãà ÃÃà b ,low; , intermediate; , marked; CE, contrast enhancement. This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. Primary Tumors of the Spine Orguc, Arkun 283 Fig. 1 A sclerotic bone island in the upper half of the corpus of the C5 vertebra (arrows). (a)T2-weightedsagittal,(b) T1-weighted sagittal images show a small lesion with low signal intensity, (c) lateral X-ray. The focus of enostosis with irregular margins has high density similar to cortical bone. typically solitary lesion; however, multiple lesions are related male predominance. Most patients experience pain that to osteopoikilosis, osteopathia striata, and melorheostosis. worsens at night and is relieved by nonsteroidal anti-inflam- matory drugs.4,5 The pain may also be aggravated by the Osteoid Osteoma imbibing alcohol. Osteoid osteoma is a benign bone tumor that occurs most Osteoid osteomas are small (by definition < 2.0 cm in frequently in young patients, 7 to 25 years of age, with a slight diameter) vascular lesions with well-organized This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. Fig. 2 A 60-year-old female patient with intraosseous vacuum in the upper plate and body of the L5 vertebrae mimicking an enostosis on magnetic resonance imaging (arrows). (a) T1-weighted coronal, (b) short tau inversion recovery coronal images demonstrate a well-defined focus with low signal. (c) Anteroposterior lumbar X-ray and (d) axial computed tomography image show the intraosseous air density with surrounding sclerosis, related to adjacent degenerative disk disease. Seminars in Musculoskeletal Radiology Vol. 18 No. 3/2014 284 Primary Tumors of the Spine Orguc, Arkun Fig. 3 Osteoid osteoma of the posterior elements of the D10 vertebra in an adolescent boy with back pain worsening at nights.