Malignant Perivascular Epithelioid Cell Tumor of the Uterus.

Perivascular epithelioid cell tumors (PEComa) are soft tissue tumors. They belong to the family of mesenchymal tumors and include angiomyolipomas, clear cell sugar tumors of the lung, and PEComas not otherwise specified (NOS). Tuberous sclerosis complex 1 (TSC1) and tuberous sclerosis complex 2 (TSC2) gene mutation is associated with PEComa, which causes hyperactivation of the mammalian target of rapamycin (mTOR) signaling pathway. In some cases, transcription factor E3 (TFE3) gene fusion is also observed. They are usually found in middle-aged women with clinical symptoms of abnormal uterine bleeding and pelvic pain. Radical surgical resection with clear margins is the mainstay of the treatment. We encountered a 54-year-old woman who had postmenopausal abnormal uterine bleeding. A hysterectomy was planned, but pelvic adhesions were discovered during the procedure. As a result, she underwent an exploratory laparotomy with hysterectomy, appendectomy, and total omentectomy. The biopsy of the uterus, left ovary, and a small bowel nodule revealed diffuse growth of epithelioid cells with eosinophilic granular cytoplasm with HMB45 staining, which indicated PEComa. A treatment plan with an mTOR inhibitor nab-sirolimus was proposed for the patient. Early detection, a multidisciplinary approach, and timely treatment are crucial for better disease prognosis.