Genetic studies indicate that PEComa can be sporadic or a component of TSC (including TSC1 and TSC2), implying that it is a TSC-associated tumor (9) which is an autosomal dominant genetic condition produced by germline mutations in SC1 on chromosome 9 or TSC2 on chromosome 16 (10). The gene discussed is TSC1; the disease is neoplasm with perivascular epithelioid cell differentiation.