The development of an elevated lesion associated with colitis cystica profunda in the transverse colonic mucosa during the course of ulcerative colitis: report of a case

We report the case of a 53-year-old man with a long history of ulcerative colitis in whom an elevated lesion in the epithelium of the affected transverse colon was initially diagnosed as a benign inflammatory polyp by endoscopic biopsies. After 4 years of follow-up, because the tumor had enlarged and villous components were endoscopically observed on the surface, a colonic resection was performed. The tumor was found to consist of hyperplastic colonic epithelium associated with multiple mucinous cysts lined with dysplastic colonic epithelial cells. Moreover, the mucinous cysts were primarily located beneath the submucosal layer and appeared to intrude into the muscularis propria of the colonic wall. This lesion had a unique pathological feature, presumably indicating neither benign inflammatory epithelium nor a neoplastic lesion of the colonic epithelium. Mucinous cysts lined with colonic epithelial components in the muscularis propria suggest a loss of normal integrity of the colonic wall. Areas of the epithelial cell lining of the mucinous cysts showed apparent structural and nuclear atypia and positive expression for p53, suggesting that this portion of the specimen was dysplastic epithelium. These pathological findings may indicate one longitudinal aspect of tumor development which could provide evidence of premalignant change or initial pathological features during the long-standing course of ulcerative colitis.