Immunosuppression and sebaceous tumors: a confirmed diagnosis of Muir-Torre syndrome unmasked by immunosuppressive therapy.

Muir-Torre syndrome (MTS) is an autosomal dominant genodermatosis caused by mutations in the DNA mismatch repair genes MLH1 and MSH2. This case describes a patient with an extensive family history of colon cancer who experienced the onset of multiple sebaceous adenomas and carcinomas after undergoing kidney transplantation and receiving immunosuppressive therapy. The finding of deficient MSH2 expression in the immunohistochemical analysis of a sebaceous carcinoma prompted genetic testing for a systemic mutation in the mismatch repair gene. A systemic mutation of the MSH2 gene was detected and, despite the absence of a visceral malignancy, the diagnosis of MTS was made. Immunosuppression has previously been thought to play a possible role in unmasking a latent MTS phenotype in transplant recipients, but systemic mutations have not previously been analyzed. The relationship between immunosuppression and sebaceous tumors with the possibility of unmasking a MTS phenotype in transplant recipients is discussed.