Background/Purpose:Because severe dysplasia and carcinoma in children with familial adenomatous polyposis (FAP) younger than 18 years is rare,earlier surgical intervention is not common. The purpose of this study is to report the prevalence of dysplasia and carcinoma among children with FAP in our institution. Methods:From 1998 through 2004,children 18 years or younger with FAP that underwent total proctocolectomy at a large children’s hospital were retrospectively reviewed. Results:Eleven children underwent surgery for FAP. The mean age at surgery was 13 ± 3.2 years. Approximately half of the patients who underwent preoperative endoscopy had evidence of dysplasia. Nine (82% ) patients had dysplasia on preoperative biopsy and/or operative specimen,and 3 (27% ) of these patients had severe dysplasia or carcinoma in situ. Four of the 5 patients without symptoms had evidence of dysplasia. No patients had invasive carcinoma. Conclusion:We observed a higher incidence of severe colonic dysplasia in young children with FAP compared with the current literature. A significant number of patients with dysplasia at surgery had no symptoms and no evidence of dysplasia on preoperative endoscopic biopsies. These data suggest that earlier intervention in children with FAP may be beneficial and should be investigated further. Background / Purpose: Because severe dysplasia and carcinoma in children with familial adenomatous polyposis (FAP) younger than 18 years is rare, earlier surgical intervention is not common. The purpose of this study is to report the prevalence of dysplasia and carcinoma among children with FAP in our institution. Methods: From 1998 through 2004, children 18 years or younger with FAP that underwent total proctocolectomy at a large children’s hospital were retrospectively reviewed. Results: Eleven children underwent surgery for FAP. The mean age at surgery was 13 ± 3.2 years Nine (82%) patients had dysplasia on preoperative biopsy and / or operative specimen, and 3 (27%) of these patients had severe dysplasia or carcinoma in situ. Four of the 5 patients without symptoms had evidence of dysplasia. No patients had invasive carcinoma. Conclusion: We observed a higher incidence of severe colonic dysp lasia in young children with FAP compared with the current literature. A significant number of patients with dysplasia at surgery had no symptoms and no evidence of dysplasia on preoperative endoscopic biopsies. These data suggest that earlier intervention in children with FAP may be beneficial and should be investigated further.