2024 Volume 42 Issue 2 Pages 214-221
Synopsis: Epithelioid sarcoma is a rare soft-tissue sarcoma which is classified into proximal type and distal type. We report a case of advanced proximal epithelioid sarcoma of the Douglas pouch that was successfully treated with first-line chemotherapy. The patient was a 39-year old woman, gravida 2, para 2. She felt buttock pain ten months after the delivery of her second child. She visited her primary care physician, who noted a mass in the Douglas' pouch on transvaginal ultrasound sonography. Subsequent examination revealed a rectal tumor, multiple liver metastases, peritoneal dissemination, and diaphragmatic dissemination. We performed an omental biopsy under diagnostic laparoscopy. Microscopically, poorly cohesive tumor cells were densely arranged in sheets, and rhabdoid-like cells were observed. Immunohistochemistry showed a complete absence of INI1 expression. We diagnosed proximal-type epithelioid sarcoma. Comprehensive genomic profiling revealed a SMARCB1/INI1 deficiency, which supported the epithelioid sarcoma diagnosis. She received docetaxel and gemcitabine and achieved a complete response.
