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Colonic polyposis syndromes

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Dr Santosh Narayankar

Publicada em: Saúde e medicina
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Colonic polyposis syndromes

  1. 1. Colonic Polyposis Syndromes
  2. 2. Definition GI polyposis refers to the presence of numerous polypoid lesions throughout the GI tract. Classified on the basis of the histological type of polyp and the clinical presentation Most are associated with increased risk of colon cancer
  3. 3. Classification of GI Polyposis Syndromes
  4. 4. Familial Adenomatous Polyposis Genetics- Most common Autosomal dominent 1 in 5000 to 7500 1 mutated APC allele is inherited. Ch 5q21-22 region,encodes 2844 amino acids
  5. 5. APC protein is a multifaceted regulator of colonic epithelial cell homeostasis cell proliferation, migration, differentiation, apoptosis, and chromosomal segregation
  6. 6. Schematic diagram of the APC gene
  7. 7. Adenomatous Polyposis Syndromes
  8. 8. Clinical features Colonic Findings 100 to thousands of adenomatous polyps Less likely before 12 yrs Avg age 25yrs ,symptomatic by 33yrs The average age for the diagnosis of adenomas was 36 years, for cancer 39 years, and for death from cancer, 42 years; 90% of FAP cases have been diagnosed by the time the patient is 50. All varieties of adenomas
  9. 9. Symptomatic patients >asymptomatic Most polyps are <1cm CRC inevitable 10-15yrs 25% have CRC at Colectomy
  10. 10. Upper GI lesions Gastric polyps occur in 30% to 100% of patients, and curiously, most polyps in the stomach are non-neoplastic fundic gland polyps. These polyps are typically 1- to 5-mm sessile growths characterized microscopically by hyperplasia of fundic glands and microcysts. Dysplasia in FAP-associated fundic gland polyps has been directly associated with larger polyp size, increased severity of duodenal polyposis, and antral gastritis, and it is inversely associated with use of acid- suppressive therapy and the presence of Helicobacter pylori.
  11. 11. A newly described autosomal dominant syndrome termed gastric adenocarcinoma with proximal polyposis of the stomach(GAPPS) may mimic the FAP phenotype in the stomach in that there are numerous fundic gland polyps in the proximal stomach that often harbor dysplasia. Unlike FAP, patients with GAPPS are at very high risk of gastric adenocarcinoma and typically have no duodenal polyps and few if any colonic adenomas.
  12. 12. Duodenal adenomas occur in 60% to 90% of FAP patients, incidence increases with age. Propensity for periampullary region As many as 50% to 85% of FAP patients manifest adenomatous change of the ampulla of Vater, As a consequence, a 4% to 12% lifetime incidence of duodenal cancer (usually periampullary) has Collectively, These adenocarcinomas are the major cause of cancer death after prophylactic colectomy in FAP patients.
  13. 13. Jejunal adenomas have been detected in 40% And ileal adenomas in 20% of FAP patients. Fortunately, malignant transformation at these sites is rare
  14. 14. Extraintestinal Features. Osteomas Bone abnormalities include osteomas of the mandible, skull, and long bones; exostoses; and various dental abnormalities including mandibular cysts, impacted teeth, and supernumerary teeth. Congenital hypertrophy of the retinal pigmented epithelium(CHRPE) Pigmented lesions in fundus in 90%,63% have >4 lesions
  15. 15. Desmoid Tumours (diffuse mesenteric fibromatosis ) 4% to 32% of patients and rank second, after metastatic carcinoma, among lethal complications of the disease. Increased incidence after prophylactic sx F>M Desmoids cause GI obstruction; constrict arteries, veins, and ureters; and are associated with a 10% to 50% mortality rate. Sulindac,Tamoxifen Others include,fibromas,lipomas,epidermoid cysts
  16. 16. Neoplasms of the biliary tree, liver, and adrenal glands also occur in these syndromes, and papillary carcinoma of the thyroid occurs in 1% of patients with FAP, predominantly in female patients. Hepatoblastoma is rare and can affect very young children inFAP families.
  17. 17. Genetic Testing and Counseling 20% are negative If it is successful in 1 family member, this test is nearly 100% accurate for identifying other gene carriers in that family. New technology has made APC gene sequencing more feasible and affordable. Absence of a mutation in the affected person suggests that genetic testing of at-risk relatives is not likely to yield clinically useful information and that the family should be screened by clinical tests.
  18. 18. Colonoscopy The presence of more than 100 polyps and the confirmation that these are adenomas establish the phenotypic diagnosis of FAP. Genetic testing of family members
  19. 19. Treatment Surgery- Total proctocolectomy either with a conventional ileostomy or as a restorative proctocolectomy with ileal pouch-anal anastomosis Subtotal colectomy with ileorectal anastomosis (IRA) can be considered, bearing in mind that the rectal segment will remain at risk for carcinoma, and the patient will have to comply with periodic surveillance examinations.
  20. 20. Medical management ascorbic acid (4 g/day), alpha-tocopherol (vitamin E, 400 mg/day), and supplemental fiber (22.5 g/day) Sulindac Celocoxib 400mg bd Aspirin 600mg/d
  21. 21. Screening