Rhabdomyosarcoma with Pseudolipoblasts Arising in Ovarian Carcinosarcoma: A Distinctive Postchemotherapy Morphologic Variant Mimicking Pleomorphic Liposarcoma
We describe a case of ovarian carcinosarcoma occurring in a 60-year-old female. The neoplasm was excised after neoadjuvant chemotherapy and contained a predominant heterologous pleomorphic rhabdomyosarcomatous component in which there were numerous multivacuolated rhabdomyoblasts that strongly mimicked lipoblasts. The clear cell variant of rhabdomyosarcoma is rarely documented, but this case shows a highly unusual finding in which the rhabdomyoblasts show the prominent multivacuolation with nuclear indentation characteristic of and indistinguishable from pleomorphic lipoblasts. This appears to represent a posttreatment phenomenon. As this finding might conceivably occur in other rhabdomyosarcomas after chemotherapy, we highlight the potential for diagnostic confusion with pleomorphic liposarcoma, which is usually diagnosed by morphology so that immunohistochemistry for muscle markers might not be performed. 1. Introduction Carcinosarcomas of the gynaecological tract (malignant mixed Mullerian tumors; MMMT) are neoplasms composed of malignant epithelial and mesenchymal components that most frequently arise in the uterus but also occur at a variety of other sites in the genital tract. Heterologous mesenchymal differentiation can occur toward a variety of lineages, including to rhabdomyosarcoma, chondrosarcoma and osteosarcoma, and more rarely liposarcoma. Here, we present a case of ovarian carcinosarcoma with heterologous pleomorphic rhabdomyosarcomatous differentiation, which was excised after neoadjuvant chemotherapy and showed a morphologically striking pattern of lipoblast-like rhabdomyoblasts. This is in keeping with an unusual posttreatment degenerative change, and we highlight its potential for diagnostic error as pleomorphic liposarcoma. 2. Case Report A 60-year-old female presented acutely with fever, abdominal pain, and a palpable mass after several months’ history of mild abdominal discomfort and bloating. She was previously fit and healthy, without significant past medical or family history. Computed tomography (CT) and magnetic resonance imaging (MRI) scans showed complex solid cystic bilateral adnexal masses measuring up to 11？cm and consistent with malignant ovarian tumor, with bulky pelvic and paraaortic lymphadenopathy. No other disease foci were noted. CA125 was raised at over 2000？IU/mL, but CA153, CA19-9, CEA, AFP, and BHCG were all within normal range. She was treated with intravenous antibiotics, and the pelvic lesion was biopsied. Needle core biopsy showed high grade serous adenocarcinoma, in keeping with either primary peritoneal,
References
[1]
L. R. Begin, W. Schurch, J. Lacoste, J. Hiscott, and D. A. Melnychuk, “Glycogen-rich clear cell rhabdomyosarcoma of the mediastinum: potential diagnostic pitfall,” American Journal of Surgical Pathology, vol. 18, no. 3, pp. 302–308, 1994.
[2]
J. K. C. Chan, H.-K. Ng, K. Y. Wan, S. Y. Tsao, T. W. T. Leung, and K. C. Tse, “Clear cell rhabdomyosarcoma of the nasal cavity and paranasal sinuses,” Histopathology, vol. 14, no. 4, pp. 391–399, 1989.
[3]
A. A. Ahmed and M. Tsokos, “Sinonasal rhabdomyosarcoma in children and young adults,” International Journal of Surgical Pathology, vol. 15, no. 2, pp. 160–165, 2007.
[4]
C. Sergi, K. Kulkarni, K. Stobart, G. Lees, and M. Noga, “Clear cell variant of embryonal rhabdomyosarcoma: report of an unusual retroperitoneal tumor- case report and literature review,” European Journal of Pediatric Surgery, vol. 22, no. 4, pp. 324–328, 2012.
[5]
D. Govender and R. Chetty, “Clear cell (glycogen-rich) rhabdomyosarcoma presenting as cervical lymphadenopathy,” ORL, vol. 61, no. 1, pp. 52–54, 1999.
[6]
F. Boman, J. Champigneulle, C. Schmitt, P. Beurey, J. Floquet, and L. Boccon-Gibod, “Clear cell rhabdomyosarcoma,” Pediatric Pathology and Laboratory Medicine, vol. 16, no. 6, pp. 951–959, 1996.
[7]
P. Jani and C. C. Ye, “Massive bone marrow involvement by clear cell variant of rhabdomyosarcoma with an unusual histological pattern and an unknown primary site,” Journal of Clinical Pathology, vol. 61, no. 2, pp. 238–239, 2008.
[8]
R. Kitazawa, S. Kitazawa, Y. Nishimura, T. Kondo, and C. Obayashi, “Lung carcinosarcoma with liposarcoma element: autopsy case,” Pathology International, vol. 56, no. 8, pp. 449–452, 2006.
[9]
D. Y. Baschinsky, J. H. Chen, M. S. Vadmal, J. G. Lucas, R. R. Bahnson, and T. H. Niernann, “Carcinosarcoma of the urinary bladder—an aggressive tumor with diverse histogenesis: a clinicopathologic study of 4 cases and review of the literature,” Archives of Pathology and Laboratory Medicine, vol. 124, no. 8, pp. 1172–1178, 2000.
[10]
C. A. Bloxham, M. K. Bennett, and M. C. Robinson, “Bladder carcinosarcomas: three cases with diverse histogenesis,” Histopathology, vol. 16, no. 1, pp. 63–67, 1990.
[11]
A. Lowichik, H. Zhou, T. J. Pysher, L. Smith, R. Lemons, and C. M. Coffin, “Therapy associated changes in childhood tumors,” Advances in Anatomic Pathology, vol. 7, no. 6, pp. 341–359, 2000.
[12]
C. M. Coffin, A. Lowichik, and H. Zhou, “Treatment effects in pediatric soft tissue and bone tumors: practical considerations for the pathologist,” American Journal of Clinical Pathology, vol. 123, no. 1, pp. 75–90, 2005.
[13]
C. M. Coffin, J. Rulon, L. Smith, C. Bruggers, and F. V. White, “Pathologic features of rhabdomyosarcoma before and after treatment: a clinicopathologic and immunohistochemical analysis,” Modern Pathology, vol. 10, no. 12, pp. 1175–1187, 1997.
