Primary Hepatic Perivascular Epithelioid Cell Tumors: From Diagnosis to Treatment

Primary hepatic perivascular epithelioid cell tumors (PEComas) are rare mesenchymal neoplasms that involve both melanocytic and smooth muscle differentiation. Primary hepatic PEComas remain a challenging condition for radiologists, pathologists, and surgeons. Our review provides an updated, clinically oriented synthesis of the available evidence on primary hepatic PEComas, integrating recent developments in diagnosis, imaging, histopathology, molecular biology, prognostic stratification, surgical and systemic treatment, and long-term surveillance. Although the majority of hepatic PEComas generally exhibit a slowly progressive clinical course, a small subgroup of them is characterized by aggressive biological behavior with an increased risk of recurrence, distant metastases, and disease-related mortality. As PEComas can resemble other hypervascular liver lesions such as hepatocellular carcinoma and hemangioma, preoperative diagnosis based on imaging techniques can be very difficult. Furthermore, the final diagnosis is usually made by histopathological examination of the surgical specimen, which reports characteristic expression of both smooth muscle markers and melanocytic markers such as HMB-45 and Melan-A. Although mTOR inhibitors have demonstrated antitumor activity in advanced PEComas, evidence specifically supporting their use in primary hepatic PEComas remains limited. Prognostic stratification, treatment selection, and long-term follow-up of primary hepatic PEComa remain major challenges. Further multicenter studies are needed to improve risk assessment and develop evidence-based guidelines for the management of these rare primary liver neoplasms.