A treated case of high-grade serous adenocarcinoma of ovary recurring as metastatic carcinosarcoma with rhabdomyosarcomatous differentiation

This case report describes a rare case of high-grade serous carcinoma of ovaries recurring as metastatic carcinosarcoma with heterologous rhabdomyosarcomatous differentiation. A 42-year-old pre-menopausal female patient presented with abdominal fullness and distention. Biopsy from the multiloculated pelvic mass confirmed the diagnosis of high-grade serous carcinoma. The patient underwent neoadjuvant chemotherapy, followed by cytoreductive surgery and post-operative chemotherapy. However, her disease progression was suspected in the follow-up with a raised serum CA-125 level and newly developed metastatic masses on radiology. She was ultimately diagnosed with metastatic carcinosarcoma through repeat biopsy from the internal mammary lymph node. Immunohistochemistry analysis confirmed the rhabdomyosarcomatous differentiation. The literature search reported a limited number of such cases, and none of them from India. This report describes the clinical course, histopathological findings, and treatment details of a patient, along with a brief literature review.