Malignant uterine perivascular epithelioid cell tumor: histopathologic and immunohistochemical characterization of a rare tumor in a post-menopausal woman |
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Authors: | Arpitha Kollabathula Parikshaa Gupta Chandan Krushna Das Divya Awasthi Radhika Srinivasan |
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Affiliation: | 1. Department of Pathology, Post Graduate Institute of Medical Education and Research, Chandigarh, India ; 2. Department of Cytology and Gynecologic Pathology, Post Graduate Institute of Medical Education and Research, Chandigarh, India ; 3. Department of Radiotherapy, Post Graduate Institute of Medical Education and Research, Chandigarh, India ; 4. Department of Obstetrics and Gynecology, Fortis Hospital, Mohali, Punjab, India |
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Abstract: | Background: Perivascular epithelioid cell tumors (PEComas) are rare, mesenchymal neoplasms composed of epithelioid cells exhibiting myogenic and melanocytic differentiation. The uterus is an infrequent site of involvement. The most common histopathologic mimics include leiomyosarcoma, endometrial stromal sarcoma, undifferentiated uterine sarcoma, and malignant melanoma. Rendering an accurate histopathologic diagnosis is essential, owing to the prognostic and therapeutic implications. Case: A 65-years-old post-menopausal woman presented with post-menopausal bleeding, abdominal pain, and heaviness for the last four months. Ultrasound abdomen revealed a large uterine mass replacing the endometrial cavity. She underwent a total abdominal hysterectomy with bilateral salpingo-oophorectomy. Result: Microscopically, a circumscribed tumor with tumor cells arranged in sheets and interlacing fascicles, with interspersed fine capillary network, was seen. The individual tumor cells were epithelioid to spindle with moderate pleomorphism, round nuclei, vesicular chromatin, prominent macronucleoli, and moderate cytoplasm. Mitosis was 2-3/50 HPFs. On immunohistochemistry, tumor cells were positive for HMB-45, Melan-A, and smooth muscle actin and were negative for h-caldesmon, TFE3, S-100, CD10, and pan-cytokeratin. Based on the histopathologic and immunohistochemical features, a final diagnosis of malignant uterine PEComa was rendered. Conclusions: This index report describes the characteristic histopathologic and immunohistochemical features of malignant uterine PEComa and highlights the salient features that distinguish it from other commonly encountered histopathologic mimics. |
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Keywords: | PEComa perivascular epithelioid cell tumor uterine PEComa histopathology HMB-45 Cathepsin K PNL2 immunohistochemistry |
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