Papillary thyroid carcinoma as first and isolated neoplastic disease in a Lynch syndrome family member with a germline MLH1 mutation

The Lynch syndrome (LS) is an autosomal dominant disorder characterized by a strongly increased risk of developing colorectal cancer and several extra-colonic malignancies, such as carcinomas of the endometrium, ovary, ureter, stomach, and small intestine [1]. Lynch syndrome is caused by germline mutations in mismatch repair genes (MMR)[2], mainly in MLH1 and MSH2 , rarely in MSH6 and PMS2 [3,4]. Tumors usually develop at a relatively young age (<50 years). Some cancers, rare in this syndrome, can be incidentally diagnosed in one of the Lynch syndrome family members. Here we report the case of unusual presentation of papillary thyroid carcinoma in a young woman carrying the c.545+3A>G mutation (rs267607760)in MLH1 gene.