Colonic adenomatous polyps involving submucosal lymphoglandular complexes

Hee Eun Lee, Tsung-Teh Wu, Vishal S. Chandan, Michael Torbenson, Taofic Mounajjed

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

Lymphoglandular complexes (LGCs) are lymphoid nodules containing intestinal mucosa, present in close apposition to muscularis mucosae or submucosa. Rarely, colorectal adenomas involve submucosal LGCs, simulating invasive adenocarcinoma with associated submucosal lymphoid aggregates, and presenting a diagnostic pitfall. We aimed to identify distinctive histologic features between submucosal LGCs and true invasion. Seven adenomas (tubular/tubulovillous adenomas [n=6], including 4 with high-grade dysplasia and 1 with focal intramucosal adenocarcinoma, and sessile serrated adenoma [n=1]) were in the right (n=5) and left colon (n=2). Seven adenocarcinomas were in the right (n=3), left (n=2), and rectum/rectosigmoid colon (n=2). Adenomatous glands involving submucosal LGCs were invested in lamina propria, showed continuity with surface adenoma, were well rounded and contained within lymphoid tissue, and predominantly lacked classic features of "pseudoinvasion." One case showed a herniation pattern carrying muscularis mucosae. Adenocarcinomas had at least one of the following features: Infiltrating single cells/small clusters (n=5), poorly formed, fused, and irregular glands (n=2), solid tumor nests (n=1), desmoplastic reaction (n=5), intraluminal necrosis (n=3), or lymphovascular invasion (n=1). In contrast, no adenoma had these features. Adenocarcinomas showed no herniation, but connection to surface tumor (n=5) was seen. Five invasive adenocarcinomas extended into the submucosa beyond the lymphoid aggregate. In conclusion, adenomas involving LGCs are a rare, clinicopathologically distinct form of pseudoinvasion that mimics invasive adenocarcinoma; histologic features that distinguish them are a well-rounded contour contained within the lymphoid tissue, and lack of infiltrating single cells/small clusters, poorly formed, fused, and irregular glands, solid tumor nests, desmoplastic reaction, and lymphovascular invasion.

Original languageEnglish (US)
Pages (from-to)1083-1089
Number of pages7
JournalAmerican Journal of Surgical Pathology
Volume42
Issue number8
DOIs
StatePublished - Aug 1 2018

Fingerprint

Colonic Polyps
Adenomatous Polyps
Adenoma
Adenocarcinoma
Mucous Membrane
Lymphoid Tissue
Colon
Neoplasms
Intestinal Mucosa
Rectum
Necrosis

Keywords

  • colorectal adenoma
  • colorectal carcinoma mimicker
  • lymphoglandular complex
  • misplaced epithelium
  • pseudoinvasion

ASJC Scopus subject areas

  • Anatomy
  • Surgery
  • Pathology and Forensic Medicine

Cite this

Colonic adenomatous polyps involving submucosal lymphoglandular complexes. / Lee, Hee Eun; Wu, Tsung-Teh; Chandan, Vishal S.; Torbenson, Michael; Mounajjed, Taofic.

In: American Journal of Surgical Pathology, Vol. 42, No. 8, 01.08.2018, p. 1083-1089.

Research output: Contribution to journalArticle

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