A Case Report of Multifocal PEComa Affecting the Pancreas and Liver and a Literature Review

Abstract

Background: Perivascular epithelioid cell tumor (PEComa) is a rare tumor derived from soft tissues and organs. Its morphology includes several types such as angiomyolipoma, lymphangiomyomatosis and pulmonary clear-cell “sugar” tumor with similar immunophenotype. Multifocal PEComa is a rarer lesion, which would cause confusion in imaging examination and clinical management. We reported a case of multifocal angiomyolipoma in pancreas and liver. At the same time, we reviewed the literature to explore the clinicopathological characteristics and possible pathogenesis of multifocal PEComa.Case presentation: A 28-year-old woman presented with a lesion in the head of the pancreas and liver 5/6 segment respectively, initially suspected of pancreatic tumor with liver metastasis. In the liver mass resection and pancreatic mass biopsy, it was found that the two lesions had similar pathological morphology. The tumor cells were mainly epithelioid and spindle cells arranged in nests pattern and partially radially distributed around blood vessels. The tumors had no malignant manifestations in morphology. Immunohistochemical assay showed that the tumor cells expressed melanocytic and smooth muscle markers. A diagnosis of pancreatic and liver angiomyolipoma was rendered.Conclusion: Based on the case we reported here and the other 12 cases we reviewed for the study, multifocal PEComa with no indications of malignancy based on morphology is biologically benign and has a good prognosis. The lesion may be caused by the blood dissemination of tumor cells rather than metastasis. Radical treatment should not be used in clinical management. In addition, follow-up for PEComa would be long-term, because a second PEComa lesion may appear many years later for the “benign” dissemination of tumor cells.