TSC1 and neoplasm with perivascular epithelioid cell differentiation: Although often treated with cytotoxic chemotherapy regimens, these have shown modest benefit.4 Some patients with PEComas benefited from treatment with mTORC1 inhibitors (including sirolimus, everolimus, and temsirolimus), as described in case reports and retrospective analyses.4-9 PEComas commonly have loss-of-function mutations in or deletions of TSC1 or TSC2.