Perivascular Epithelioid Cell Tumor (PEComa) of Pancreas: Diagnosed Preoperatively by Endoscopic Ultrasound-Guided Fine-Needle Aspiration

Summary: Perivascular epithelioid cell tumors (PEComas) of the pancreas are extremely rare mesenchymal tumors and to our knowledge, only 17 cases have been reported in the English literature to date. We report our experience with a new case of primary pan- creatic PEComa diagnosed preoperatively by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) comple- mented by tissue cell block and immunohistochemistry. The patient was a 54-year-old female whose chief complaint was intermittent severe right upper quadrant abdominal pain. Computed-tomography (CT) imaging revealed a mass between the head and the body of the pancreas. EUS-FNA smear prepa- ration was obtained but was nondiagnostic. However, examina- tion of the tissue cell block showed sheets of epithelioid cells with abundant eosinophilic cytoplasm and immunohistochemistry studies revealed positivity for both melanocytic (HMB-45 and Melan-A) and smooth muscle markers (actin and desmin). A diagnosis of PEComa was made and an uncomplicated middle pancreatectomy was performed. Our case and review of the lit- erature demonstrates that EUS-FNA complemented with tissue cell block increases cellular yield, improved preoperative diag- nostic accuracy, and may assist the surgeon in planning conser- vative surgical management.