J Korean Soc Radiol.  2018 Jul;79(1):40-44. 10.3348/jksr.2018.79.1.40.

Mucinous Adenocarcinoma Arising within a Colonic Diverticulum Mimicking a Diverticular Abscess: A Case Report

• Choi G
• Hwang J
• Hong SS
• Kim JJ
• Choi IH

• KMID: 2416404
• DOI: http://doi.org/10.3348/jksr.2018.79.1.40

Abstract

Colon cancer arising in a colonic diverticulum is very rare. There are only a few reported cases of colon cancer associated with a diverticulum. Of these reported cases, only a few are those of a mucinous adenocarcinoma. Here, we report a case of an 82-year-old female with a mucinous adenocarcinoma arising in the ascending colonic diverticulum, which clinically and radiologically mimicked perforated diverticulitis with abscess formation. Although such cases are rare, our findings suggest that malignant tumors may be misdiagnosed as diverticular diseases and should be considered during work-up.

MeSH Terms

Abscess*
Adenocarcinoma, Mucinous*
Aged, 80 and over
Colon*
Colon, Ascending
Colonic Neoplasms
Diverticulitis
Diverticulum
Diverticulum, Colon*
Female
Humans
Mucins*
Mucins

Figure

• 

  Fig. 1 A 82-year-old female with a mucinous adenocarcinoma arising in ascending colonic diverticulum. A. Axial contrast-enhanced abdominal CT showing a peripheral-enhancing, low-attenuated, exophytic mass at the medial wall of the proximal ascending colon. The mass is connected to the lumen of the proximal ascending colon via an out-pouching sac (arrowhead), indicating a colonic diverticulum. Mild soft tissue stranding was noted in the surrounding fat. B. In the coronal reformatted image, the involved segment of the colon shows mural thickening with preservation of the layering pattern (arrows). The appendix is unremarkable. C. The opened lumen of the colon specimen showing a large diverticular opening (arrow) with intact overlying mucosa. D. Cut section revealed an irregular mass in pericolic soft tissue, involving the colonic wall (6.0 × 5.5 cm). E. The mucosa lining the diverticulum is eroded (arrow) along the diverticular opening (asterisk). An abundant mucin pool with tumor cell nests was present in the deeper portion of the diverticulum (hematoxylin and eosin stain, × 12.5). F. The mass has floating, single, or nested tumor cells in the mucin pool (hematoxylin and eosin stain, × 100).

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