Navigating PEComa: Bridging Sarcoma and Gynecologic Oncology Perspectives for Accurate Diagnosis and Treatment

Dr. Edwin Choy from the sarcoma oncology program and Dr. Sarah Bouberhan from gynecologic medical oncology at Massachusetts General Hospital discussed perivascular epithelioid cell tumors (PEComas), rare mesenchymal neoplasms affecting approximately 75% of patients with benign or uncertain malignant potential. PEComas occur predominantly in women aged 20 to 55 years, commonly affecting the uterus, kidney, retroperitoneum, gastrointestinal tract, liver, and lungs. Diagnosis requires expert pathological evaluation with specific immunohistochemical markers including melanocytic markers (HMB-45, Melan-A) and smooth muscle markers (SMA, desmin, caldesmon). Molecular characterization reveals approximately 50% harbor TSC1 or TSC2 loss affecting mTOR pathway signaling, whereas others demonstrate TFE3 gene rearrangements. The AMPECT phase 2 trial established nab-sirolimus as FDA-approved first-line therapy for advanced disease, demonstrating 39% response rates with 10.6-month progression-free survival and 40.8-month overall survival. Patients with TSC2 mutations showed nearly 90% response rates versus 13% for non-TSC2 mutations.