PEComas may be associated with the tuberous sclerosis complex (TSC), an autosomal dominant neurocutaneous disorder caused by genetic alterations of the TSC1 (9q34) or TSC2 (16p13.3) genes [11], and characterized by mental retardation, seizures and multiple tumors in different sites [12]. The gene discussed is TSC1; the disease is neoplasm with perivascular epithelioid cell differentiation.