Uterine Leiomyoma with Peculiar Skeletal Muscle Like and Rhabdoid Cells - Case Discussion and Literature Review

June 2015 KUWAIT MEDICAL JOURNAL 149

Case Report Uterine Leiomyoma with Peculiar Skeletal Muscle Like and Rhabdoid Cells - Case Discussion and Literature Review

Rajan Arora, Amany Abou-Bakr, Raeda Albannai Department of Pathology, Farwaniya Hospital, Kuwait

Kuwait Medical Journal 2015; 47 (2): 149 - 152

ABSTRACT

to as rhabdoid cells. Intra and extra-cytoplasmic hyaline (rhabdomyoma, rhabdomyosarcoma) and extra-renal globules were observed in these cells. However, no cross rhabdoid tumors have been reported in uterus but cases of uterine leiomyoma with skeletal muscle like cells or cells smooth muscle origin (positive for desmin and h-caldesmon resembling those of extra-renal rhabdoid tumors are rare. while negative for cytokeratin, myogenin, myoglobin, We describe clinical and pathological features of one such and myo D1). We also review the pertinent literature and case of typical uterine leiomyoma in which histopathology emphasize that presence of such cells may lead to problems showed presence of rounded, polygonal, and strap cells having abundant eosinophilic cytoplasm with round to oval is important so that overtly aggressive management of a nuclei, some of which were eccentric in position referred benign tumor is avoided.

KEYWORDS: leiomyoma, skeletal muscle like cells, uterus

INTRODUCTION diagnosed as simple hyperplasia on histopathology. Presence of skeletal muscle like cells or cells Subsequently, she underwent a total abdominal resembling those of extra-renal rhabdoid tumors is hysterectomy and bilateral salpingo-oophorectomy. rarely reported in uterine leiomyomas[1-,3], although Pathology: On gross examination an intramural (rhabdomyoma, rhabdomyosarcoma) and extra-renal leiomyoma measuring 3 cm in maximum diameter was rhabdoid tumors have been described in uterus[4-7]. The presence of these cells can cause diagnostic was no hemorrhage or necrosis. Rest of the specimen was unremarkable except for two small simple cysts muscle tumors, smooth muscle tumor of uncertain malignant potential, or tumors with skeletal muscle presence of simple hyperplasia of endometrium along features of one such case which showed skeletal grossly showed rounded, polygonal or strap cells muscle like cells or rhabdoid cells, review the pertinent having abundant deeply eosinophilic cytoplasm (Fig. literature, and discuss the potential problems in 1). They have round to oval and some eccentric nuclei with nuclear enlargement and prominent nucleoli. Intra and extra-cytoplasmic hyaline globules were CASE REPORT observed in some cells (Fig. 2). No cross striations : A 45-year-old lady presented to our gynecological OPD with complaint of bleeding or necrosis. On immunostaining, these cells stained per vagina for three years. An endometrial sampling positively for vimentin, desmin, and h-caldesmon (Fig. was performed to know the etiology and she was 3), and were negative for cytokeratin, myogenin, and

Address correspondence to: Dr. Rajan Arora, Senior Specialist, Department of Pathology, Farwaniya Hospital, P O Box 18373, Farwaniya 81004, Kuwait. Tel: +965-60486105, +965- [email protected] 150 Uterine Leiomyoma with Peculiar Skeletal Muscle Like and Rhabdoid Cells - Case Discussion ... June 2015

Fig 1: Photomicrograph showing strap shape cells with skeletal Fig 2: Photomicrograph showing intra and extra cytoplasmic muscle like or rhabdoid appearance (H&E, X 400). hyaline globules (H&E, X 400).

case. They interpreted them as exhibiting immature muscle cells of the fetal uterus and were designated leiomyoblastoma. In another report[9] on eight atypical (bizarre) leiomyomas, the authors described these cells. Only one of them was examined ultra- structurally and an association of rhabdoid cells with atypical bizarre leiomyomas was suggested. Since all of their cases were obtained from consultive typical leiomyomas. Our case reveals the occurrence of rhabdoid cells in a typical leiomyoma. Recently an analysis of 10 typical and two atypical leiomyomas describe the occurrence of these cells highlighting the Fig 3: Photomicrograph demonstrating strong positive presence of intra-cytoplasmic inclusion bodies. Two of immunostaining for desmin (DAB, X 400). their cases showed these bodies in more than 80% of [10] myo D1 proving them to be of smooth muscle origin. tumor cells . A diagnosis of leiomyoma with skeletal muscle like or rhabdoid cells was rendered. The patient is doing well muscle cells of leiomyomas and myometrium after one and half year of follow-up. and usually show positive reaction for SMA, desmin, DISCUSSION and vimentin, patho-genetically the inclusion bodies Skeletal muscle like cells or cells resembling those found in the present and previously reported cases of extra-renal rhabdoid tumors are rarely seen in may be related to abnormal aggregates of actin or uterine leiomyomas. They have distinctive appearance on light microscopy and are referred to as “rhabdoid [10] cells”. They show round, polygonal, or strap shape In the study of Dundr et al , two types of inclusions with abundant deeply eosinophilic cytoplasm and were found by electron microscopy. One of them was may contain intra / extra cytoplasmic globules / appearance. They do not display cross striations and inclusions were eosinophilic, PAS negative, and at have eccentric round to oval nuclei with vesicular least at the periphery actin, desmin, and h-caldesmon to coarse chromatin and conspicuous nucleoli. Two positive. Another type of inclusions was composed out of the three tumors studied by Watanabe et al[8] in 2003 contained these cells like the present case structure. These inclusions were basophilic, or including intense immunoreactivity for vimentin and unstained on H&E, were PAS positive and showed desmin. However, h-caldesmon was focal rather than negative immunohistochemical staining. They suggest that the dense granular bodies may represent June 2015 KUWAIT MEDICAL JOURNAL 151

smooth muscle tumors often are immunoreactive for cytokeratin, and negative for smooth muscle markers. related to globules named Thanatosomes related to Absence of high mitosis and true necrosis separate cell injury and apoptosis[11,12]. the case described from smooth muscle tumors of low malignant potential. with rhabdoid cells is tumors with skeletal muscle CONCLUSION reports of leiomyomas with skeletal muscle cells Presence of peculiar skeletal muscle like cells or in the literature, and both documented convincing cells resembling extra-renal rhabdoid tumor in uterine histologic, immunohistochemical, and ultrastructural leiomyoma represent smooth muscle cells with an [2,3]. unusual phenotype. This entity must be kept in mind and needs to be distinguished from uterine tumors in uterine tumors is most commonly observed as a with rhabdomyomatous or rhabdosarcomatous rhabdomyosarcomatous component in a malignant mixed mullerian tumor or mullerian adenosarcoma. such cells can cause diagnostic dilemma leading Pure uterine rhabdomyosarcomas occur but are to erroneous diagnosis and overtly aggressive most commonly of cervical origin[4,13]. These can be management. distinguished from present case morphologically (presence of pleomorphism, mitosis, and cross REFERENCES striations) and immunohistochemically (Myo D1, myogenin positive). Rhabdomyoma is another 1. Hendrickson MR, Kemson RL. Surgical pathology of the uterine corpus. In: Bennington JL, ed. Major lower female genital tract. problems in pathology series. Vol 12. Philadelphia: WB Pure malignant rhabdoid tumors of uterus are rare Saunders; 1980. [6,7,14] and this diagnosis is one of exclusion as rhabdoid 2. MartinReay DG, Christ ML, Lapata RE. Uterine phenotype is reported in endometrial stromal sarcoma, epithelioid smooth muscle tumors, leiomyosarcoma, of a case. Am J Clin Pathol 1991; 96:344-347. and malignant mixed mullerian tumor[15-18]. Although 3. Fornelli A, Paquinelli G, EusebiV. Leiomyoma of the our case revealed clearly benign features and has background population of typical leiomyoma cells, report. Hum Pathol 1999; 30:356-359. the rounded cells seen were similar to extra-renal 4. Jaworski RC, Rrncoret RH, Moir DH. Pleomorphic rhabdoid tumors. Extra-renal rhabdoid tumors exhibit rhabdomyosarcoma of the uterus. Case report with hyaline eosinophilic globular inclusions, vesicular a review of the literature. Br J Obstet Gynaecol 1984; nuclei, central prominent nucleoli, and are positive 91:1269-1273. for vimentin and cytokeratin. In our case, these 5. Jacques SM, Lawrence WD, Malviya VK. Case report. cells were positive for vimentin, and smooth muscle Mixed embryonal rhabdomyosarcoma and fetal markers, but not cytokeratin. That the rhabdoid cells rhabdomyoma. Gynecol Oncol 1993; 48:272-276. in our case demonstrated evidence of smooth muscle 6. Cho KR, Rosenshein NB, Epstein JI. Malignant rhabdoid tumor of the uterus. Int J Gynecol Pathol variant expression of the smooth muscle phenotype 1989; 8:381-387. and would be expected to have the benign outcome of 7. Hsueh S, Chang TC. Malignant rhabdoid tumor of the the leiomyomas. uterine corpus. Gynecol Oncol 1996; 61:142-146. 8. Watanabe K, Ogura G, Suzuki T. Leiomyoblastoma and the immunophenotype is equivocal, molecular of the uterus: an immunohistochemical and analysis of the hSNF5 / INI1 gene or immunostaining electron microscopic study of distinctive tumours for the INI1 product may assist in revealing the correct with immature smooth muscle cell diagnosis[19]. mimicking fetal uterine myocytes. Histopathology 2003; 42:379-386. include epithelioid smooth muscle tumors and smooth 9. Parker RL, Young RH, Clement PB. Skeletal muscle- muscle tumors of uncertain or low malignant potential. like and rhabdoid cells in uterine leiomyomas. Int J The cells of epithelioid smooth muscle tumors Gynecol Pathol 2005; 24:319-325. characteristically are devoid of rhabdoid phenotype 10. Dundr P, Povýsil C, Tvrdík D, Mára M. and have granular eosinophilic or clear cytoplasm and Uterine leiomyomas with inclusion bodies: an immunohistochemical and ultrastructural analysis of and eccentrically placed nuclei. In addition epithelioid 12 cases. Pathol Res Pract 2007; 203:145-151. 152 Uterine Leiomyoma with Peculiar Skeletal Muscle Like and Rhabdoid Cells - Case Discussion ... June 2015

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