colonic polyps

colonic polyps

1. non-neoplastic

   • inflammatory
     • purely inflammatory lesion
     • presentation
       • associated with chronic disease
         • usually asymptomatic. Dx by follow up and screening
       • not associated with chronic disease
         • clinical triad
           • 1.rectal bleeding
           • 2.mucus discharge
           • 3.inflammatory lesions of the anterior rectal wall
     • etiology
       • impaired relaxation of anorectal sphincter creating a sharp angle of the anterior rectal shelf, leads to recurrent rectal ulceration. chronic cycles of injury and healing produce polypoid mass made up of inflamed and reactive mucosal tissue
     • morphoogy
       • gross: inflamed mucosa and can appear in both forms (sessile, pedunculated)
       • microscopic: crypt abscess, inflamatory cells (neutrophils), if chronic you see granulation tissue
   • hamartomatous
     • it is a disorganized tumor like growth composed of mature cell types
     • hamartomatous ployposis syndrome are rare associated with intestinal and extra-intestinal manifestations and you need to screen family members
     • juvenile polyps are most common, they can be sporadic (in adults) or syndromic (in children younger than 5 year old)
     • presentation
       • mostly located in the rectum so presented by rectal bleeding.
       • rectal prolapse and the polyp is seen.
     • morphology
       • gross
         • solitary in sporadic
         • multible in syndromic
         • typically pedunculated, smooth surfaced show cystic space in cut section
       • microscopically
         • dilated gland, inflammatory debris and neutophils, mucosal hyperplasia.
     • peutz-jeghers syndrome
       • it is rare syndrome. defined by the presence of multiple GIT hamartomatous polyps.
       • associated with increase risk of malignancies of colon, pancreas, breast, lung, ovaries, uterus and testes
       • most commonly seen in small intestine.
   • hyperplastic
     • it is common type of polyps, seen in 60-70 year old
     • etiology isn't completly understood but thought to be a decreased epithelial cell turnover and delayed sheding of epithelial cells leading to pileup of goblet cells
     • sessile serrated adenomas are similar lesions that have a malignant potential
     • morphology
       • mostly seen in the left colon. particulary, in the sigmoid and rectum.
       • grossly it is a smooth nodular protrusions of the mucosa
       • microscopically it is composed of mature goblet and absorptive cells. crowding of cells create serrated surface there is no dysplasia

2. neoplastic

   • benign
     • adenoma
       • 1. tubular
         • small pedunculated polyos composed of small, rounded and tubular glands
       • 2. tubulvillous
         • is a mix of tubular and villous adenomas
       • 3. villous
         • larger and sessile. long slender projections resembles the intestinal villi (higher risk of malignancy)
       • 4. sessile serrated adenomas
         • have features overlaping between hyperplastic and adenoma. there is no dysplasia
           • serrated structure throgh the full lenghth of the gland
           • crypt dilatation
           • osenophelia
       • are benign polyps that give rise to colorectal adenocarsinoma
       • is characterized by epithelial dysplasia
         • dysplasia: nuclear hyperchromasia, elongation and stratification.
         • epithelum fails to mature, immature epithelum at the surface of adenoma.
         • stalks containing prominent blood vessels
       • grossly: hemorrhage, necrosis.
     • familial syndromes
       • familial adenomatous polyposis
       • inherted syndromes associated with colonic polyps and higher risk of cancer
   • malignant
     • adenocarsenoma