16年の経過観察の後に浸潤癌となった盲腸SSA/Pの一例

抄録

A SSA/P in the right colon, which transformed to an invasive submucosal adenocarcinoma finally, was endoscopically observed in a 67-year-old woman. 16 years prior to the surgery, a sessile elevated lesion (approximately 15 mm in diameter) was detected in the cecum. 20 months before surgery, a lusterless reddish part emerged in the polyp, in which a few atypical glands as adenoma were detected by biopsy. On colonoscopy 18 months later, the reddish part changed into a roughly elevated tumor. We diagnosed it as a submucosal cancer with a serrated lesion and performed ileocecal resection. Histological examination revealed moderate to poorly differentiated adenocarcinoma with a serrated lesion. This case suggests that the right-side SSA/Ps should be removed immediately, considering the potential for rapid progression to deep and extensive cancer.