Urachal cyst with huge abscess in adults Fig. 1. Computed tomography showed huge abscess containing fluid and gas below umbilicus. Fig. 2. The operative findings. Abscess cavity and urachus was completely removed. Thin fibrous band was observed between abscess cavity and the middle of mesentery, but there was no communication with small bowel. Fig. 3. Microscopic findings. (A) Variable sized multilocular cysts or ducts lined by urothelial, cuboidal or columnar epithelium. Some large cysts were lined by flattened epithelium (H&E, ×20). (B) The cystic lumen contains some histiocytes and lymphocyte infiltration is observed in the lining epithelium (H&E, ×40). (C) Low power view shows multiple inflammatory cell infiltration and surrounding fibrosis around fistula tract of umbilicus (H&E, ×4). thesurgery.or.kr 255