Lipoma of the colon with overlying hyperplastic epitheliumdownloads.hindawi.com/journals/cjgh/1997/547175.pdf · Lipoma of the colon with overlying hyperplastic epithelium Jasim M

Lipoma of the colon withoverlying hyperplastic

epitheliumJasim M Radhi MB ChB FRC(Path) FRCPC, TH Brian Haig MD FRCSC FACS

Hyperplastic polyp-type epithelium can be seen in juve-nile polyps, Peutz-Jeghers polyps, inflammatory polyps

and especially inflammatory cloacogenic polyps of the analregion (1). To our knowledge this is the first report of such acomplex colonic lesion exhibiting an unusual juxtapositionof diverticular disease and submucosal lipoma with hyperpla-sia of the overlying mucosa.

Although colonic lipoma may have no clinical signifi-cance, the overlying mucosa, like the rest of colonic mucosa,is subject to any pathological process.

CASE PRESENTATIONA 45-year-old man presented with acute abdomenal painand, at operation, was found to have a large lipoma of the sig-moid colon adjacent to diverticulitis with perforation andabscess formation. He had been passing blood per rectum forabout one year. The resected specimen consisted of 10 cm ofsigmoid colon with an inflammatory mass. On opening thecolon there was a 5 cm yellowish mass overlying the area ofinflammation (Figure 1). The colonic wall was thickenedand a few diverticula were present. Microscopic examination

confirmed diverticulitis with perforation and abscess forma-tion. Within the mass was a tumour composed of mature adi-pose tissue covered by hyperplastic, and serrated epitheliumconsisting of columnar and goblet cells (Figure 2a). Featureswere similar to those seen in hyperplastic polyps of the colon(Figure 2b).

DISCUSSIONIntestinal lipomas are uncommon; they are more often seenin the large than the small intestine and are more frequent inthe right than the left colon. These lesions tend to be solitarybut may be multiple in 20% or more of the cases (2). Theyusually arise from the submucosa and may protrude into thelumen, causing symptoms depending on the lesion size. Theymay cause colonic obstruction, intussusception or a palpablemass. Biopsy may be needed when visual identification anddistinction from adenomas cannot be ascertained. Pathol-ogically, they are composed of well-circumscribed, matureadipose tissue with varying amounts of fibrous stromacovered with intact colonic mucosa. However, ulceration,necrosis, cystic degeneration and calcification are known

694 Can J Gastroenterol Vol 11 No 8 November/December 1997

JM Radhi, THB Haig. Lipoma of the colon with overlying hy-perplastic epithelium. Can J Gastroenterol 1997;11(8):694-695. Lipomas of the colon are submucosal nonepithelial tumourscovered by intact or eroded mucosa. A large colonic lipomapresent in close proximity to an area of diverticulitis is presented.The lining mucosa in this case exhibited hyperplastic changes,reminiscent of those seen in hyperplastic polyps. The signifi-cance of such mucosal changes are highlighted because adenoma-tous or even carcinomatous transformation, though rare, remainspossible.

Key Words: Diverticular disease, Epithelial hyperplasia, Lipoma

Lipome du côlon avec chevauchement del’épithélium hyperplasique

RÉSUMÉ : Les lipomes du côlon sont des tumeurs non épithélialessous-muqueuses couvertes par une muqueuse intacte ou érodée. Ondécrit ici le cas d’un volumineux lipome du côlon à proximité d’unezone de diverticulite. La muqueuse dans ce cas manifestait desanomalies hyperplasiques rappelant les anomalies typiques des polypeshyperplasiques. La portée de ces anomalies de la muqueuse sontsoulignées parce que, quoique rare, la possibilité de transformationadénomateuse, voire carcinomateuse, est toujours possible.

Departments of Pathology and Surgery, Royal University Hospital, University of Saskatchewan, Saskatoon, SaskatchewanCorrespondence and reprints: Dr JM Radhi, Department of Pathology, Royal University Hospital, University of Saskatchewan, 103 Hospital

Drive, Saskatoon, Saskatchewan S7N 0W8. Telephone 306-655-2221, fax 306-655-2223, e-mail [email protected] for publication July 16, 1997. Accepted October 20, 1997

BRIEF COMMUNICATION

complications. Inflammatory changes may be extensive, lead-ing to abnormalities in fat cells suggestive of sarcomatouschanges; such lesions have been termed atypical lipomas (3).

Rectal bleeding from diverticular disease of the colon iscommon; in addition, lipomas may ulcerate and lead to rec-tal bleeding. The lipoma in this case was large and at the siteof diverticular disease. It may have played a role in the ob-struction of a diverticulum and the subsequent developmentof diverticulitis. Moreover, the covering epithelium of thelipoma showed hyperplasia with features reminiscent of a hy-perplastic polyp. The epithelium was serrated and comprisedboth columnar and goblet cells, lacking atypia or mitotic ac-tivity, which could represent a hyperplastic response to mu-cosal injury or an erosion, be due to the fusion of severalhyperplastic polyps or represent a large hyperplastic polyp.

CONCLUSIONSAs indicated, hyperplastic polyp type epithelium can be seenin juvenile polyps, Peutz-Jeghers polyps, inflammatory pol-yps and especially inflammatory cloacogenic polyps of theanal region (1). Regenerative changes due to ischemia mayalso lead to mucosal hyperplasia. However, we believe thefindings in this case are more likely a true hyperplastic polyp.There was no ulceration of the mucosa, and the bleeding inthis case was attributed to diverticular disease. The majorityof hyperplastic polyps are small, rarely larger than 1 cm in di-ameter. In 10% of cases hyperplastic polyps are multiple, andit is not uncommon to find up to five or 10 polyps, particu-larly in the distal colorectum. Hyperplastic polyps are notconsidered to be premalignant but do sometimes exhibit ar-eas of adenomatous change, and hyperplastic-like epithe-lium is occasionally found to coexist with adenomatous areaswithin the same polyps. There are also isolated reports of car-cinoma arising within mixed hyperplastic adenomatous pol-

yps (4-6), and rarely carcinoma originating within pure hy-perplastic polyp has been described (7). Removal ofasymptomatic colonic lipoma is not necessary because it hasno clinical significance (8). However attention should bepaid to the overlying mucosal changes.

REFERENCES1. Cooper H. Intestinal neoplasia. In: Stenberg SS, ed. Diagnostic

Surgical Pathology, vol 2, 2nd edn. New York: Raven Press,1994;1371-7.

2. Gordon RT, Beal JM. Lipoma of the colon. Arch Surg 1978;113:897-9.3. Shover DC. Atypical lipomas of the colon. Report of two cases with

pseudo malignant features. Dis Colon Rectum 1984;27:485-7.4. Cooper HS, Patchefsky AS, Marks G. Adenomatous and

carcinomatous changes within hyperplastic colonic epithelium.Dis Colon Rectum 1979;22:152-6.

5. William CT, Arthur JF, Bussey HJR, Morson BC. Metaplastic polypsand polyposis of the colorectum. Histopathology 1980;4:155-70.

6. Urbonski ST, Kossakowska AE, Marcon N, et al. Mixed hyperplasticadenomatous polyps – an under diagnosed entity. Report of a case ofadenocarcinoma arising within a mixed hyperplastic adenomatouspolyp. Am J Surg Pathol 1984;8:551-6.

7. Franzin G, Novelli P. Adenocarcinoma occurring in a hyperplastic B(metaplastic) polyp of colon. Endoscopy 1982;14:28-30.

8. Luck GD. Colonic polyps: Benign and premalignant neoplasm of thecolon. In: Yamada T, Alpes DH, Onyang C, et al, eds. Textbook ofGastroenterology, vol 2, 2nd edn. Philadelphia: JB LippincottCompany, 1995:1928-9.

Can J Gastroenterol Vol 11 No 8 November/December 1997 695

Colon lipoma with hyperplastic epithelium

Figure 2) A Low power view of colonic lipoma with hyperplasia of themucosa; B Closer view highlighting the close resemblance to a hyperplasticpolyp

Figure 1) Resected sigmoid colon with inflammatory mass and submuco-sal lipoma

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Lipoma of the colon with overlying hyperplastic epitheliumdownloads.hindawi.com/journals/cjgh/1997/547175.pdf · Lipoma of the colon with overlying hyperplastic epithelium Jasim M