“…Despite the extreme rarity of both MF and MTS, our patient represents the third reported case of MF in a patient with MTS. 12 , 13 Evidence of MSI-H and MLH1 promoter hypermethylation in both MF and MTS suggests a subset of MF cases might share the same molecular pathogenesis as cases of sebaceous neoplasms or gastrointestinal malignancies in MTS. A disease association notwithstanding, MLH1 and MSH2 might have clinical relevance in MF.…”