Variante de
- Hereditary Non-Polyposis Colorectal Cancer Syndrome (HNPCC/Lynch syndrome)
Inheritance
- Autosomal dominant
Mutation
- Variante do síndrome de Lynch
- Mutations in Mismatch Repair (MMR) genes → microsatellite instability
- Most common mutations: MSH2 (90%) > MSH6, MLH1, PMS-2
Clinical presentations
- Cutaneous
- Sebaceous adenoma, sebaceoma, sebaceous carcinoma
- Extrafacial sebaceous neoplasms are very strongly indicative of Muir-Torre
- Multiple keratoacanthomas (often with sebaceous differentiation)
- Fordyce spots on the oral mucosa
- Também CBCs, mas menos comum
- Adenoma SebáceoSebaceoma
- Extracutaneous cancers
- Colon (most common, 50%) > GU (second most common)
- Gastric, ovarian, endometrial, lung, breast, lymphoma
Histopathology diagnostic pearl
- Immunohistochemistry should be performed on all sebaceous adenomas and carcinomas
- 100% PPV: loss of MLH1 and MSH6; MSH2, MLH1, MSH6
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