Tumors characterized by the presence of HMB45-positive perivascular epithelioid cell (PEC) - A novel entity in surgical pathology

Perivascular Epithelioid Cell (PEC) is a recently identified novel cell type expressing both markers of muscle nature and melanogenesis. PEC has been identified in numerous lesions, such as angiomyolipoma, lymphangioleiomyomatosis, lymphangioleiomyoma and clear cell 'sugar' tumor. We have proposed the unifying concept of a family of lesions characterised by the presence of PECs. Most of these lesions are strictly related to the genetic syndrome of tuberous sclerosis (TS). Some of these lesions can mimic other tumors, particularly clear cell carcinomas and clear cell sarcomas. The importance of a correct diagnosis is stressed by the fact that most PEC lesions have a benign clinical behaviour. Here we summarise our recent experience on this family of tumors.