Colitis cystica profunda presenting with a mucus pool within the stalk of a pedunculated colon polyp

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A 38-year-old man was admitted for a colon polypectomy. A colonoscopic examination had been carried out in another hospital several days earlier due to hematochezia and a polyp had been found in the sigmoid colon. The 1.5-cm, pedunculated polyp ([Fig. 1]) had a slight bulge in the stalk, and there was a mucosal bridge at the attachment to the intestinal wall, mimicking a submucosal tumor.

Fig. 1 Colonoscopy showing a 1.5-cm, pedunculated polyp in the sigmoid colon, with a bulging stalk and a mucosal bridge on the attachment of the colonic wall, implying the presence of a submucosal mass in the stalk.

The polyp was resected at the midportion of the stalk using an electrosurgical unit (ERBE VIO 300D, Elektromedizin GmbH, Tubingen, Germany) and snare (SD-9U-1, Olympus, Tokyo, Japan). Grossly, the resected specimen was composed of a head portion and stalk containing yellowish mucus. The remaining part of the stalk in the intestinal wall also contained the yellowish mucus ([Fig. 2]).

Fig. 2 a, b After endoscopic polypectomy, part of the stalk remained attached to the intestinal wall and was seen to contain a large amount of yellowish mucus.

Histologic examination revealed that the polyp was a typical mixed hyperplastic and adenomatous type, composed of tubular adenoma with low grade dysplasia, adjacent to which was a hyperplastic polyp ([Fig. 3 a, b]).

Fig. 3 a Histologically, the polyp was a mixed adenomatous and hyperplastic type. There was abundant fibrous tissue and several dilated cystic glands in the submucosa, suggesting colitis cystica profunda (hematoxylin and eosin, magnification × 10). b Typical tubular adenoma on the left and hyperplastic polyp on the right, with a distinctive transition between the two elements (hematoxylin and eosin, magnification × 40). c The dilated cystic gland deep within the stalk remnant was filled with mucin (Alcian blue stain, magnification × 12.5).

Also, there were multiple mucus-filled cysts under the muscularis mucosa. The cysts were covered with columnar epithelium and were surrounded by fibrous tissue. A large mucus pool in the epithelial lining was seen near the stalk remnant ([Fig. 3 c]). We speculated that the pool of mucus within the stalk stump had resulted from submucosal invasion of the epithelial gland, as seen in colitis cystica profunda.

Colitis cystica profunda is a rare disorder in which benign, epithelial-lined, mucus-filled cysts, of unknown etiology, develop in the mucosa and submucosa of the colon and form polypoid lesions [1]. The disease is rarely accompanied by adenoma. A case report of a single polypoid colitis cystica profunda lesion accompanied by adenocarcinoma on the surface was recently published [2]. However, there has not been any report of a mucus pool within the stalk of a mixed hyperplastic and adenomatous colonic polyp, mimicking submucosal tumor, in colitis cystic profunda.

Competing interests: None

Endoscopy_UCTN_Code_CCL_1AD_2AB

References

• 1 Gordon P H. Miscellaneous entities.  In: Gordon PH, Nivatvongs S (eds). Principles and practice of surgery for the colon, rectum, and anus.  St. Louis; Quality Medical Publishing 1999: 1394-1396
• 2 Mitsunaga M, Izumi M, Uchiyama T. et al . Colonic adenocarcinoma associated with colitis cystica profunda.  Gastrointest Endosc. 2009;  69 759-760