P242 Incidence and management of extra colonic manifestations in familial adenomatous polyposis: a tertiary center experience

IntroductionFamilial adenomatous polyposis (FAP) is an autosomal dominant genetic disorder characterised by numerous (>100) colorectal adenomatous polyps. Individuals with FAP in addition to developing polyps within other part of the gastrointestinal tract are at risk of developing other extra intestinal manifestations. Studies have correlated the prominence of extra intestinal manifestations to specific mutations within the adenomatous polyposis coli (APC) gene1. We report the Incidence and management of extra intestinal manifestation in patients with FAP managed at a tertiary centre with correlation to the APC gene mutation.MethodologyWe performed a retrospective study of patients with confirmed FAP managed between 2007–2020 in a large tertiary referral centre. Baseline data including APC gene mutations, the extra intestinal manifestations and overall management were recorded for all patients.Results14/44(31.8%) patients with FAP had extra intestinal manifestations with a median age of 33 when the FAP gene was identified and a female predominance of 71%. 13 different APC gene mutations were observed but with no clear association with each extra intestinal manifestation. 28.5% died as a consequence of their disease. Table 1 summarise these findings.ConclusionExtra intestinal manifestations are frequently observed in patient with FAP. Therefore, regular follow up of patients are required to optimise care for this group of patients.Abstract P242 Table 1 Extra Intestinal manifestation Gene mutations Number of patients (n=14) Management (Surgical intervention undertaken for each patient) Papillary cancer of the thyroid c.7513C>T 1 Total Thyroidectomy Desmoid tumour of small bowel mesentery c.2481dupT (p.Thr828fs) ,c.2805C>A (p.Tyr935X),c.2493dupA (p.Pro832fs),c.706C>T,c.5795del 5 1-Small bowel bypass surgery2-Enterectomy and multi visceral transplant3-Sub-total enterectomy4.Observation5.Observation Pancreatic NET c.1187G>Ac.3329C>G p.(Ser1110*)c.2493dupA (p.Pro832fs) 3 1-Right posterior sectionectomy of pancreas2-Distal pancreatectomy and splenectomy3-Right posterior sectionectomy of pancreas Desmoid tumour of the pelvis c.4031C>Gc.3927_3931del 2 1.Observation2. Hysterectomy and oorphectomy Ameloblastoma c.3927_3931del 1 Observation Fibromatosis of Para spinal space extending c.3909A>G 1 Observation Fibromatosis of the anterior abdomen whole gene deletion 1 Observation Breast fibromatosis c.5795del 1 Wide breast excision Low grade oligo astrocytoma of the tem