Gardner Syndrome (GS)
Definition	Subtype of familial adenomatous polyposis (FAP) characterized by colonic polyposis and extracolonic manifestations
Genetics	- Mutations in the adenomatous polyposis coli (APC) gene - Autosomal dominant inheritance - 80% of cases are familial
Clinical Presentation	1. Colonic manifestations: - Hundreds to thousands of adenomatous polyps - Onset: 2nd to 3rd decade of life 2. Cutaneous manifestations: - Epidermal cysts (most common) - Fibromas - Lipomas - Pilomatricomas 3. Osteomas: - Typically in facial bones - Range from solitary to dozens - Size: few mm to cm in diameter 4. Desmoid tumors: - Affect ~10% of GS patients - Most common in abdomen or abdominal wall 5. Ocular manifestations: - Congenital hypertrophy of retinal pigmented epithelium (CHRPE) - Usually asymptomatic - Multiple bilateral lesions 6. Dental abnormalities (30% of patients): - Hypodontia - Unerupted and supernumerary teeth - Odontomas - Abnormal tooth morphologies
Associated Malignancies	- Colorectal cancer (almost inevitable if untreated) - Duodenal cancer - Thyroid cancer - Gastric cancer - Pancreatic cancer
Diagnosis	1. Detailed family history 2. Sigmoidoscopy/Colonoscopy 3. Ophthalmologic examination 4. Panoramic dental radiographs 5. Genetic testing
Management	2. Annual sigmoidoscopy starting age 10-12 3. Annual thyroid examination 4. Abdominal CT every 3 years starting age 20-25 5. Genetic counseling for family members 6. Dental referral if needed
Complications	- Colorectal cancer (main cause of death if untreated) - Other associated malignancies - Desmoid tumors (locally invasive)