Two cases of perivascular epithelioid cell tumor of the uterus: clinical, radiological and pathological diagnostic challenge

BACKGROUND Perivascular epithelioid cell tumor (PEComa) is a rare subtype of mesenchymal origin tumor composed of epithelioid cells which exhibits immunohistochemical co-expressions of melanocytic markers and smooth muscle markers. CASE PRESENTATION In the first case, malignant uterine PEComa with vaginal and multiple lung metastasis was misdiagnosed preoperatively as uterine leiomyosarcoma despite a preoperative punch biopsy and immunohistochemical analysis of the metastatic vaginal mass. In the second case, synchronous uterine PEComa showing benign histology with lymph node involvement was incidentally detected after a staging operation for ovarian cancer. Definitive diagnosis of uterine PEComa was achieved only after hysterectomy despite preoperative assessment with pelvic magnetic resonance imaging and punch biopsy of metastatic lesion. CONCLUSION The authors report two rare cases of uterine PEComa diagnosed postoperatively based on the morphologic and immunohistochemical features.