다발성 전이를 동반한 후복막강 악성 혈관주위상피모양세포종양

Perivascular epithelioid cell tumors (PEComas) are unusual mesenchymal neoplasms composed of histologically and immunohistochemically distinct perivascular epithelioid cells (PECs). Although PEComas have the potential to behave in a malignant fashion, malignant PEComas arising from the retroperitoneum are extremely rare. A 68-year-old woman presented with a painful palpable mass in her left upper abdomen. Computed tomography of the abdomen showed a 9 cm sized heterogeneous mass in left para-aortic space and multiple hypervascular nodules in the liver. 18F-fludeoxyglucose-PET/CT showed multifocal hypermetabolic lesions in retroperitoneum, liver, and skeletal bones. Percutaneous needle biopsies were done on the retroperitoneal and hepatic mass. Both specimens were positive for human melanoma black-45 (HMB-45) on histological and immunohistochemical staining which was compatible with PEComas. Herein, we report a rare case of retroperitoneal PEComa with multiple metastases involving liver and bone at initial diagnosis that exhibited aggressive behavior and resulted in a devastating prognosis. (Korean J Gastroenterol 2014,64:302-306)