Small Intestine and Colon Pathology 3 Flashcards
Inflammatory Polyp associations
- -Solitary rectal ulcer syndrome
- -Ulcerative colitis
- -Crohn’s disease
How do inflammatory polyps present?
Inflammatory, non-neoplastic process in GI tract
Inflammatory pseudopolyps
In UC and CD. Represent inflamed and regenerating mucosa that projects above the level of surrounding mucosa (often ulcerated)
Inflammatory pseudopolyp pathology
Mix of acute inflammation, dense mucosal lymphoplasmacytic infiltrate, distorted dilated crypts w/surface erosion, cryptitis, crypt abscesses
Juvenile polyps (Retention polyps)
- -Can occur sporadically or as result of polyposis syndrome.
- -Most common type of polyp to occur in children
Gene mutations associated with juvenile polyposis syndrome
SMAD4 and BMPRIA.
Are ind. with juvenile polyposis syndrome at an increased risk for GI tract adenocarcinoma?
Yes.
Where do retention polyps usually occur?
In colon (usually rectum). Usually solitary if spontaneous. Numerous polyps often seen in polyposis syndrome and may occur in stomach, small bowel, and colon
Gross morphology of Juvenile (retention) polyps
–Rounded, smooth, unilobular w/erythematous cap of eroded tissue.
Microscopic morphology of Juvenile (retention polyps)
- -Dilated, branched, mucin-filled crypts.
- -Crypt abscesses, neutrophils, and/or eosinophil collections may be present.
- -Surrounding stroma expanded w/many mixed inflammatory cells.
Peutz-Jeghers polyps
- -Most common in small bowel
- -Seen in Peutz-Jeghers syndrome
- -Can present in childhood w/GI bleeding and intussusception
- -Increased risk of cancer
Peutz Jeghers polyp morphology
–Arborizing (branching) smooth muscle pattern w/bland mucosal proliferation and are often pedunculated.
Hyperplastic polyps
- -Small
- -Left colonic polyp
- -Most common type of adult polyp
- -Proliferative polyp w/o significant malignant potential
Adenoma (adenomatous polyp)
- -Can occur anywhere
- -Benign, but can be precursor to adenocarcinoma.
- -Removed during colonoscopy to reduce risk of malignant colorectal adenocarcinoma
Adenoma morphology
Dysplastic glandular proliferation or tubular or villous proliferation
Sessile serrated polyp (adenoma)
- -Usually in R colon.
- -Can be precursor to adenocarcinoma
Sessile serrated polyp morphology
- -Lack adenomatous epithelium
- -Prominent serration at all levels of the crypts, crypt dilation, horizontally shaped crypts, abundant goblet cells.
- -Crypt nuclei w/cytoplasmic eosinophilia, nuclear stratification, loss of cell polarity
Peutz-Jeghers Syndrome
–Multiple polyps and mucocutaneous pigmentation
What mutation can cause Peutz-Jeghers syndrome
Loss of function mutations in STK11 (tumor suppressor gene)–> increased risk of GI tract adenocarcinomas (and other cancers)
Familial adenomatosis polyposis (FAP) mutation and inheritance
- -Autosomal dominant.
- -Mutations in APC tumor suppressor gene.
Diagnosis of FAP
> 100 polyps and detection of germline mutations in APC gene
Tx of FAP
Screening in adolescence followed by post-adolescent prophylactic colectomy
FAP polyp characteristics
- -Develop large numbers in colon and rectum
- -Can get polyps in small bowel and stomach
What types of cancer are individuals with FAP at increased risk of?
Colorectal adenocarcinoma (100%) Upper GI tract adenocarcinoma (esp. at ampulla)
Gardner’s syndrome
–In addition to FAP, get desmoid (fibrous) tumors inside peritoneal cavity, osteomas, epidermal cysts, dental abnormalities, thyroid tumors
Lynch syndrome (HNPCC) mutations
Mutations in genes that encode enzymatic mismatch repair proteins. Inherit one defective allele and acquire another (mostly in microsatellite DNA)
70-80% of patients w/FAP present with what?
Hypertrophy of pigmented retinal epithelium
Lynch syndrome and risk of colorectal cancer
- -Don’t develop increased # of adenomas
- -When adenomas occur have risk of colon cancer development of 80-90%
- -Risk of small bowel carcinoma increased
Turcot syndrome
Coexistence of hereditary colon cancer syndrome along with CNS tumors
What tumor is common in Turcot syndrome with FAP? With HNPCC?
- -Medulloblastoma and FAP
- -Glioblastoma multiforme and HNPCC