Invisible colonic dysplasia

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Invisible colonic dysplasia is colonic dysplasia that is not seen on endoscopy.

General

Gross

  • Not visible - definitional.

Microscopic

Features:

  1. Nuclear changes at the surface of the mucosa - key feature.
    • Size and shape or size change:
      • Cigar-shaped (elongated) nucleus (usu. length:width > 3:1) with nuclear hyperchromasia (more blue).
      • Large round nuclei +/- vesicular appearance (clearing) -- nuclei have white space.
    • Nuclear crowding/pseudostratification - important.
    • +/-Loss of nuclear polarity (nuclei no longer on basement membrane).
  2. Loss/decrease of goblet cells (common).
  3. Cytoplasmic hyperchromasia.

Notes:

  • Nuclear changes deep to the surface are non-neoplastic if normal appearing mucosa (with small round nuclei) is superficial to it; mucosa that is more blue and atypical deep and less blue without nuclear atypia at the surface is said to be "maturing".
    • Classically, adenomatous polyps have "reverse maturation":
      • The surface is more hyperchromatic (more blue).
      • The base is more mature (more globlet cells, no nuclear changes -- less blue).
  • Ampullary adenomas often have less prominent pseudostratification and fine chromatin.

DDx:

  • Reactive changes due to inflammation.
  • Invasive adenocarcinoma.

Sign out

Submitted as "Colon Right, Biopsy":
     - Colonic mucosa with low-grade dysplasia, NEGATIVE for high-grade dysplasia, 
       see comment. 

Comment:
If the tissue was NOT a polyp on endoscopy, close follow-up, a re-examination of the history/family history and re-biopsies are suggested.

Alternate

Rectum, Biopsy:
     - Polypoid fragment of rectal mucosa with LOW-GRADE DYSPLASIA, see comment.
     - NEGATIVE for high-grade dysplasia and NEGATIVE for malignancy.

Comment:
The histomorphology would be in keeping with a tubular adenoma; however, this specimen was not submitted as a polyp. Clinical correlation is recommended. Close follow-up with re-biopsy is suggested.

See also

References

  1. Blonski W, Kundu R, Lewis J, Aberra F, Osterman M, Lichtenstein GR (2008). "Is dysplasia visible during surveillance colonoscopy in patients with ulcerative colitis?". Scand J Gastroenterol 43 (6): 698–703. doi:10.1080/00365520701866150. PMID 18569987.