adenocarcinoma


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  • Clinical

    • average age 70s
    • associations: family history, IBD, HNPCC
    • tx: resection is most effective for T1 and T2 stage. Chemo for advanced stage.
    • FAP: autosomal dominant, colon filled with polyps, APC gene, wnt pathway, tx prophylactic colectomy
    • Gardner syndrome: FAP with extracolonic features (osteomas, epidermal cysts, fibromas)
    • HNPCC: MMR/MSI, colorectal, gyn (endometrial, ovarian) and gastric cancer. Colonoscopy starting age 20 or 10 years younger than family hx
    • Turcot syndrome: CNS tumor + hereditary colonic cancer syndrome

  • Gross

    • fungating, ulcerated, or polypoid

  • Histology

    • architecture: irregular, complex crypts, cribriforming
    • pink necrotic debris in lumens
    • high grade dysplasia (round nuclei, hyperchromasia, stratification)
    • desmoplasia
    • suspect HNPCC if: lots of lymphocytes, proximal mucinous or poorly differentiated carcinoma

  • Types

  • Grading

    • well, moderately, poorly, and undifferentiated
    • based on % gland formation

  • Stains

    • positive: CK, CK20 (variable in MSI high), CEA

  • Molecular

    • sporadic: APC, KRAS, p53, 18q21 LOH (SMAD2, 4)
    • hereditary: HNPCC = mismatch repair (MSH2, MLH1, MSH6, PMS2) -> microsatellite instability

  • Signout

    • bx: superficial fragments of invasive moderately differentiated adenocarcinoma
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