Immunohistochemical analysis indicated that the PEC is strongly positive for HMB-45, can positive for Melan-A also focal with S100 and muscle-specific actin.[5,6] Besides, a group of lesions, including angiomyolipoma, lymphangiomyoma, lymphangioleiomyomatosis (LAM), renal capsuloma, and clear cell myelomelanocytic tumor of the ligamentum teres were found to share similar histological, ultrastructural and immunohistochemical features, so be also characterized by the presence of the distinctive cell type of PEC. The gene discussed is PMEL; the disease is lymphangioleiomyomatosis.