Depressed-Type Hyperplastic Lesion in the Colon

A 77-year-old man was referred for evaluation of anal bleeding. He had no history of any cancer and no family history of colorectal cancer. Colonoscopy using a magnifying videoscope (CF240ZI; Olympus, Tokyo, Japan) was performed and an advanced colon cancer at the rectum and a slightly reddish flat lesion at the ascending colon were detected. The depressed lesion in the ascending colon became obvious when sprayed with 0.2 % indigo carmine solution (Figure [1]). The lesion was about 6 mm in diameter, and the clarified margin of depression was well demarcated. The magnified view of the depressed lesion after spraying with 0.2 % indigo carmine showed a type II pit pattern and a normal round pit pattern (type I) along the marginal elevation according to the classification proposed by S. Kudo et al., indicating that this lesion was hyperplastic [1]. The patient underwent an endoscopic mucosal resection [2]. Histological examination revealed the characteristic non-neoplastic proliferation of serrated tubular profiles of a hyperplastic polyp (Figure [2]).

Figure 1 The depressed region with marginal elevation became clear at chromoendoscopy.

Figure 2 Histological appearance of the endoscopic mucosal resection (EMR) specimen showing non-neoplastic proliferation of serrated tubular profiles (hematoxylin and eosin (H&E); original magnification × 35).

There are a few reports of hyperplastic polyps with a variation in the growth pattern that have been described as ”inverted hyperplastic” polyps. The lesion in the case presented here was thought to be the initial lesion of an inverted hyperplastic polyp [3].

Endoscopy_UCTN_Code_CCL_1AD_2AC

References

• 1 Kudo S, Tamura S, Nakajima T. et al . Diagnosis of colorectal tumorous lesions by magnifying endoscopy.  Gastrointest Endosc. 1996;  44 8-14
• 2 Kudo S. Endoscopic mucosal resection of flat and depressed type of early colorectal cancer.  Endoscopy. 1993;  25 455-461
• 3 Sobin L H. Inverted hyperplastic polyps of the colon.  Am J Surg Pathol. 1985;  9 265-272