First pancreatic perivascular epithelioid cell tumor (PEComa) treated by mTOR inhibitor.

BACKGROUND: Perivascular epithelioid cell tumor, an extremely rare mesenchymal tumor, could be ubiquitous but rarely arises from pancreas. Surgery is considered the most appropriate treatment. Nevertheless, activation of mTOR pathway seems to be a common pathogenic event in PEComas paving the way to chemotherapy by mTOR inhibitor. METHOD: A 17 year-old man presented a hypervascular tumor of 55 mm, located in the head of pancreas without bile duct or pancreatic duct compression. RESULTS: Histopathology showed epithelioid cells with clear or focally granular eosinophilic cytoplasm with melanocytic (HMB-45, Melan-A) and myoid markers which confirmed diagnosis of PEComa. Given the absence of worrisome feature, we ruled out surgery and decided to initiate treatment with Sirolimus, an mTOR inhibitor. After 3.5 years, we showed a significant reduction in size of the tumor. CONCLUSION: This first case of pancreatic PEComa treated by mTOR inhibitor without surgery suggests a good efficiency of this therapy.