CTNNB1 exon 3 mutations in desmoid and other tumours

Desmoid tumours are rare soft tissue tumours. The a locally invasive monoclonal fibroblastic proliferation leading to variable clinical course. Abnormal functioning of the Wnt/APC/Beta catenin pathway accounts for large proportion desmoid There currently two genetic subtypes: sporadic resulting from somatic CTNNB1 mutations in exon 3 and associated with germline pathogenic variants APC. APC thought be mutually exclusive. Mutations also molecular subtypes other including hepatocellular adenomas childhood medulloblastomas. Using Sanger sequencing, we searched hotspot using case series 13 patients 11/13 harboured mutations. We assisted histopathological diagnosis aberrant IHC staining (hepatocellular adenoma medulloblastoma), both harbouring Hepatocellular beta high risk malignant transformation WNT-activated medulloblastomas very good prognosis. subclassification tumours, combined histopathology, assists understanding basis disease, tailoring treatment options provides informative Our laboratory offers testing.