Lynch syndrome (LS) is an autosomal-dominant inherited disorder characterized by a predisposition to colorectal cancer and extracolonic cancers (particularly endometrium, ovary, stomach, small bowel, hepatobiliary tract, pancreas, urothelial tract, brain, and skin). Muir–Torre syndrome (MTS) is considered a phenotypical variant of LS, where patients develop sebaceous neoplasms and keratoacanthomas. Currently, only few studies and case reports suggest an association between LS and other skin cancers, such as Bowens’ disease, melanoma and squamous cell carcinoma (SCC). In this case-report we describe the case of a 33-year-old woman with LS and a proven MSH2 germline mutation, presenting with a SCC on the right cheek. Immunohistochemistry lacked MSH2 and MSH6 protein staining. The tumor showed a discordance between immunohistochemistry and micro-satellite instability status, for which a clear explanation cannot be provided yet. To conclude whether this pattern is indicative for SCC occurring in LS patients, further analyses of other LS patients presenting with SCC should be carried out. Our patient’s young age and skin type (Fitzpatrick phototype VI) suggest a possible link between LS and cutaneous SCC.
Kientz C, Joly MO, Faivre L, Clemenson A, Dalac S, Lepage C et al (2017) A case report of Muir-Torre syndrome in a woman with breast cancer and MSI-Low skin squamous cell carcinoma. Hered Cancer Clin Pract 15:6CrossRefPubMedPubMedCentralGoogle Scholar
Gray SE, Kay EW, Leader M, Mabruk MJ (2006) Enhanced detection of microsatellite instability and mismatch repair gene expression in cutaneous squamous cell carcinomas. Mol Diagn Ther 10(5):327–334CrossRefPubMedGoogle Scholar
Lamba AR, Moore AY, Moore T, Rhees J, Arnold MA, Boland CR (2015) Defective DNA mismatch repair activity is common in sebaceous neoplasms, and may be an ineffective approach to screen for Lynch syndrome. Fam Cancer 14(2):259–264CrossRefPubMedGoogle Scholar
Wimmer K, Etzler J (2008) Constitutional mismatch repair-deficiency syndrome: have we so far seen only the tip of an iceberg? Hum Genet 124(2):105–122CrossRefGoogle Scholar
Gylling AH, Nieminen TT, Abdel-Rahman WM, Nuorva K, Juhola M, Joensuu EI et al (2008) Differential cancer predisposition in Lynch syndrome: insights from molecular analysis of brain and urinary tract tumors. Carcinogenesis 29(7):1351–1359CrossRefPubMedGoogle Scholar