Retroperitoneal malignant PEComa: a case report.

PEComa, or perivascular epithelioid cell tumor, is a distinctive mesenchymal neoplasm arising from perivascular epithelioid cells (PECs) that classically demonstrates a myomelanocytic immunophenotype. PEComas predominantly affect adults, with female predilection, and can occur at various anatomical sites, including the retroperitoneum, uterus, kidney, liver, and soft tissues. Most PEComas are considered benign and have an overall good prognosis. However, malignant PEComas are generally uncommon and tend to behave aggressively. In this clinical vignette, we present a 65-year-old woman with a malignant PEComa arising in the retroperitoneum with the development of metastatic disease, illustrating the importance of accurate diagnosis and potential treatment implications.