The natural history of familial adenomatous polyposis syndrome: a 24 year review of a single center experience in screening, diagnosis, and outcomes.

PURPOSE Understanding the natural history of Familial Adenomatous Polyposis (FAP) will guide screening and aid clinical management. METHODS Patients with FAP, age ≤20years presenting between 1987 and 2011, were reviewed for presentation, diagnosis, extraintestinal manifestations, polyp burden, family history, histology, gene mutation, surgical intervention, and outcome. RESULTS One hundred sixty-three FAP patients were identified. Diagnosis was made by colonoscopy (69%) or genetic screening (25%) at mean age of 12.5years. Most children (58%) were asymptomatic and diagnosed via screening due to family history. Rectal bleeding was the most common (37%) symptom prompting evaluation. Colon polyps appeared by mean age of 13.4years with >50 polyps at the time of diagnosis in 60%. Cancer was found in 1 colonoscopy biopsy and 5 colectomy specimens. Family history of FAP was known in 85%. 53% had genetic testing, which confirmed APC mutation in 88%. Extraintestinal manifestations included congenital hypertrophy of the retinal pigment epithelium (11.3%), desmoids (10.6%), osteomas (6.7%), epidermal cysts (5.5%), extranumerary teeth (3.7%), papillary thyroid cancer (3.1%), and hepatoblastoma (2.5%). Six patients died secondary to FAP. CONCLUSIONS Clinical presentation and manifestations in pediatric FAP are variable. We suggest an individualized patient-oriented screening algorithm that allows for earlier screening and appropriate management.