Fig. 2

Pathology of the larger polypoid polyp revealed polypoid colonic mucosa with atypical lymphoid cells infiltrating the lamina propria (a). An immunohistochemical study found that the specimen was positive for CD20, CD5, and Bcl-2, and negative for CD10 and cyclin D1, which supported the diagnosis of extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue lymphoma type (b). The resected specimen is positive for lymphoma cells, which are present at the cauterized margin (left side of the figure; hematoxylin and eosin stain, 100×) (c)