Abstract
A 74-year-old man visited another hospital with right lower quadrant abdominal pain. Computed tomography (CT) showed thickening of the sigmoid colon with dilatation oral to this and left hydronephrosis with thickening of the soft tissues around the abdominal aorta and inferior mesenteric artery. He was referred to Gunma University Hospital for diagnosis and therapy. Colonoscopy showed sigmoid colon cancer. On the basis of the imaging results, the ureteric stenosis was thought to be attributable to retroperitoneal fibrosis rather than lymph node metastases. We performed sigmoidectomy with D2 lymph node dissection. Dissection of the tissues around the abdominal aorta and inferior mesenteric artery was difficult. The pathological diagnoses were S, type 3, SS, N0, and stage II ; findings from the pathological analysis of the connective tissue around the inferior mesenteric artery was consistent with those of IgG4-related disease. The patient's postoperative course was uneventful, and he was discharged after 15 days. A double J stent was inserted for the left ureter stenosis in the Department of Urology. The patient was administered prednisolone to treat the IgG4-related disease. As a result, the hydronephrosis improved.
