Gastrointestinal pathologyBeginnerAnnotated

Colonic adenocarcinoma arising in tubulovillous adenoma

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Clinical history

68-year-old man with iron deficiency anaemia. Colonoscopy showed a 35 mm sigmoid polypoid lesion.

Specimen

Endoscopic polypectomy · Stain: H&E

Microscopic description

Tubulovillous architecture with high-grade dysplasia and a focus of invasive glands penetrating the muscularis mucosae into the submucosa, with a desmoplastic response.

Diagnostic question

How would you report the invasive component and which parameters determine further management?

Reveal differential diagnosis
  • High-grade dysplasia without invasion
  • Pseudoinvasion (epithelial misplacement)
Reveal final diagnosis

Moderately differentiated adenocarcinoma arising in a tubulovillous adenoma

Learning points

  • Distinguish true invasion from epithelial misplacement
  • Report depth of submucosal invasion, differentiation, lymphovascular invasion and margin distance
  • Correlate with endoscopic appearance

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