Inverted diverticulum of the colon – a cautious diagnosis

A 65-year-old male with no past clinical history, undertakes a colonoscopy due to episodic pain in lower left quadrant and constipation.

In the sigmoid colon, we identified an elevated sessile lesion, covered by normal mucosa in white light (Fig. 1) and narrow-band imaging (Fig. 2), with fine concentric folds surrounding it. It's characteristics did not change with water instillation.

Figure 1.

Inverted diverticulum in white light.

Figure 2.

Inverted diverticulum in Narrow Band Imaging.

This endoscopic appearance is typical of inverted colonic diverticulum.

Inverted diverticula are rare findings, reported in less that 0.7% of colonoscopies. It is important to make a correct diagnosis of these lesions, since their erroneous interpretation as sessile polyps, with subsequent biopsy or polypectomy, can lead to colonic perforation.

The following endoscopic characteristics should be sought while diagnosing inverted colonic diverticulum:

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  elevated sessile appearance with fine concentric pale rings surrounding the lesion, also called Aurora rings;

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  mucosal pattern on lesion similar to surrounding mucosa;

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  localization in area of diverticula;

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  lesion reverts to typical diverticular appearance with direct water infusion, air insufflation, or gentle pressure with biopsy forceps.

Conflict of interest

The authors declare having no conflict of interest.