Implications of imaging, morphologic, and immunohistochemical features of pancreatic perivascular epithelioid cell tumor: case report and comprehensive literature review.

Abstract

Background: Perivascular epithelioid cell tumor (PEComa) of the pancreas is a rare tumor of pancreatic mesenchymal origin with malignant potential. Critical to appropriate clinical management is determining whether the tumor is benign or malignant. Because of its rarity, morphologic and histologic characteristics and limited patient follow-up of pancreatic PEComa have precluded precise definition of malignancy. However, because malignant pancreatic PEComa appears to be distinctly uncommon, further improvements characterizing its preoperative imaging features could facilitate use of diagnostic endoscopic ultrasound biopsy and perhaps ablative treatment. This paper presents a case of pancreatic PEComa treated at the Affiliated Hospital of North Sichuan Medical College and includes a systematic literature review with special emphasis on the key imaging features of pancreatic PEComa.

Case presentation: In February 2024, a woman in her 50s was admitted to the hospital with subxiphoid discomfort. Magnetic resonance imaging (MRI) of the upper abdomen revealed a round, solid mass in the pancreatic uncinate process. The patient underwent pancreatic mass resection and pancreaticojejunostomy, and the diagnosis of pancreatic PEComa was confirmed through pathological examination.

Conclusions: Imaging examinations appear valuable for a tentative diagnosis of pancreatic PEComa. Key imaging features include its frequent occurrence in the pancreatic head, typically small to moderate size, "pushing" as opposed to infiltrative growth pattern with well-defined margins, and the presence of a capsule. The lesions are usually solid and often exhibit mild to moderate heterogenous enhancement during the arterial phase, with reduced enhancement in the portal and delayed phases.