Multifocal malignant perivascular epithelioid cell tumor (PEComa) of the peritoneum: A case report

Abstract

INTRODUCTION AND IMPORTANCE: Neoplasms with perivascular epithelioid-cell differentiation (PEComa) are rare. We present a case of multifocal malignant PEComas arising in the peritoneum. CASE PRESENTATION: A 61-year-old woman presented with a painful abdominal mass that had progressed over the past year and recently increased in size. Pelvic magnetic resonance imaging (MRI) showed two masses: an 11-cm partially solid and cystic tumor, with moderate contrast uptake probably originating from the left ovary, and an 18-cm sized, intraperitoneal abdominal heterogeneous enhancing mass. Two nodules in the mesentery and the bladder peritoneum were discovered intraoperatively. The patient underwent Hudson's intervention with resection of the epiploic mass and the two nodules. Microscopic examination revealed a tumor proliferation of epithelioid clear cells with delicate vascular septae. Immunohistochemistry was positive for HMB45, MelanA and SMA. The final diagnosis of a malignant PEComa was retained. The patient developed two local peritoneal recurrences and died after 26 months of follow-up. CLINICAL DISCUSSION: Our case is original by its multifocal presentation being the seventh case of a multifocal malignant PEComa reported in the literature. PEComa's clinical presentation and radiographic appearance can often mimic a soft tissue clear cell sarcoma. CONCLUSION: Clinical and pathological correlations are mandatory to make a precise diagnosis and adapt the treatment of PEComas.