Hyperplastic polyposis associated with two asynchronous colon cancers

Abstract

We report a patient with hyperplastic polyposis who had two asynchronous colon cancers, a combined adenoma-hyperplastic polyp, a serrated adenoma, and tubular adenomas. Hyperplastic polyposis is thought to be a precancerous lesion; and adenocarcinoma arises from hyperplastic polyposis through the hyperplastic polyp-adenoma-carcinoma sequence. Most polyps in patients with hyperplastic polyposis present as bland-looking hyperplastic polyps, which are regarded as non-neoplastic lesions; however, the risk of malignancy should not be underestimated. In patients with multiple hyperplastic polyps, hyperplastic polyposis should be identified and followed up carefully in order to detect malignant transformation in the early stage.

Figure 1

A: Resected sigmoid colon. The adenocarcinoma, 4.0 cm × 2.5 cm in size, shows ulcer formation with localized infiltrative growth. Multiple small polyps are seen in the resected colon (arrow); B: Well-differentiated adenocarcinoma located in the sigmoid colon (HE, × 100). High columnar tumor cells have proliferated to form papillary or tubular structures; C: Hyperplastic polyp located in the resected sigmoid colon (HE, × 100). The epithelial cells are arranged in a serrated fashion and have no atypical features.

Figure 2

A: Tubular adenoma located in the transverse colon (HE, × 100). The lesion shows duct proliferation and cells that have mild nuclear atypia; B: Hyperplastic polyp located in the transverse colon (HE, × 200). Serrated ducts with no atypical features are observed; C: Hyperplastic polyp located in the ascending colon (HE, × 100). Serrated ducts with no atypical features are observed. The inflammatory infiltration is mainly composed of lymphocytes in the lamina propria; D: High-grade serrated adenoma located in the sigmoid colon (HE, × 200). Papillary or serrated structures with obvious atypical cells are seen. Atypical structures, such as fusion of the tubular structure, are also shown. There is no evidence of malignancy.

Figure 3

Colono-scopy of the ascend-ing colon. An ulcera-tive lesion with loca-lized infiltration is located in the proxi-mal part of the asce-nding colon. The center of the tumor is necrotic and hemorr-hagic. A small subpeduncu-lated polyp is seen proximal to the tumor (arrow).

Figure 4

A: Resected ascending colon. A cancer, 2.8 cm × 3.8 cm in size, and multiple small polyps are seen. The two largest polyps are 13 mm × 8 mm and 11 mm × 4 mm in size, respectively (arrows); B: Well to moderately differentiated adenocarcinoma (HE, × 20). Atypical duct formation and cribriform pattern can be seen. The tumor infiltrates the muscular layer and reaches the subserosal layer without serosal exposure; C: A small area from the periphery of the adenocarcinoma (HE, × 20). The lower part is the hyperplastic polyp component, and the upper part is the adenocarcinoma component; D: The left side of Figure 4C (HE, × 100). A small adenoma-like component is shown in the border between the hyperplastic component and the adenocarcinoma component; E: The combined adenoma-hyperplastic polyp (HE, × 20). The polyp is 1 cm in size. The upper part is the adenoma component, which primarily consists of a tubular adenoma with mild cellular atypia, the lower part is the hyperplastic polyp component; F: A higher magnification of Figure 4E (HE, × 100). A small amount of serrated structure with mild atypia is seen at the border of the two components.