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Intramucosal fat is uncommon in large bowel polyps but raises three differential diagnoses
  1. Newton A C S Wong,
  2. Orla O'Mahony
  1. Department of Cellular Pathology, Southmead Hospital, Bristol, UK
  1. Correspondence to Dr Newton A C S Wong, Department of Cellular Pathology, Southmead Hospital, Bristol BS10 5NB, UK; Nacs.Wong{at}


Aims This case series intends to expand currently limited knowledge regarding the existence and diagnostic significance of intramucosal fat in colorectal polyps.

Methods Clinicopathological features of nine such polyps were reported following histopathological review, including S100 and EMA immunohistochemistry.

Results and conclusions Such review subdivided seven polyps into three groups: (1) mucosal perineurioma/serrated polyps with fat among the perineurial stroma (three cases); (2) submucosal lipomas with adipose tissue extending into the overlying mucosa (two cases) and (3) polyps with intramucosal adipose tissue only, that is, the newly described but less-recognised entity known as intramucosal lipoma (two cases). The two remaining polyps of this series did not include submucosa but, from assessing their muscularis mucosae, were favoured to represent intramucosal lipomas. The first two phenomena are formally described for the first time by this case series. The last of these three diagnoses should prompt investigations for Cowden syndrome, but intramucosal lipomas are more often sporadic/non-syndromic.

  • colon
  • rectum
  • polyp
  • mucosa
  • fat
  • Cowden syndrome

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  • Handling editor Runjan Chetty.

  • Contributors NACSW conceived the idea for this case series. Both authors reviewed the cases of this series and wrote the manuscript.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Patient consent for publication Not required.

  • Provenance and peer review Not commissioned; externally peer reviewed.