A subset of patients with Lynch Syndrome demonstrates cutaneous manifestations of the disorder. Characterization of these Lynch-related skin lesions could help in early recognition of patients with Lynch Syndrome. A broad search of the literature on OVID Medline and Embase was carried out to capture papers reporting cutaneous manifestations in Lynch Syndrome patients. The results were uploaded into Mendeley reference management software. The PRISMA workflow was used in the literature selection process. In this systematic review, data were collected from 961 cases from 413 studies, including 380 molecularly confirmed Lynch Syndrome cases. The main skin lesions were: Sebaceous adenomas (43%), sebaceous carcinomas (27%), keratoacanthomas (16%), sebaceomas (13%), squamous cell carcinomas (23%), and basal cell carcinomas (10%). MSH2 variants were the most common underlying genotype (72%). Assessment of mismatch repair by immunohistochemistry, microsatellite instability analysis, or both were performed on 328 skin lesions from 220 (58%) molecularly confirmed cases. In those skin lesions, 95% of Immunohistochemistry and 90% of the microsatellite instability test results were concordant with the underlying genotype. Sebaceous skin lesions are well-recognised phenotypic features of Lynch Syndrome. Our results show that squamous and basal cell carcinomas are relatively common in patients with Lynch syndrome; however, available evidence cannot confirm that Lynch syndrome is causal. Immunohistochemistry and/or microsatellite instability testing of skin tumours in patients with a family history of Lynch Syndrome-associated cancers may be a useful approach in identifying patients requiring referral to Clinical Genetics and/or consideration of germline genetic testing for Lynch Syndrome.
Keywords: Lynch syndrome; Mismatch repair; Muir-Torre syndrome; Sebaceous tumour; squamous cell cancer; basal cell cancer.
© 2022. The Author(s).