[A case of a villous tumor of the rectum with electrolyte depletion syndrome].

We report a case of a villous tumor of the rectum with electrolyte depletion syndrome (EDS). A 76-year-old woman developed general fatigue, and on investigation, we found a large laterally spreading tumor of the rectum using bowel enema and colon fiber. Pathologically, the biopsy specimen was graded Group 4. We intended to perform a laparoscopy-assisted low anterior resection in the patient. However, the operation was interrupted by a short-run type of ventricular premature contraction (VPC) due to EDS-induced hypokalemia. After treating the hypokalemia, low anterior resection or laparotomy was performed. The tumor was 19 × 13 cm in size and occupied the circumference of the rectum. Histological examination revealed well differentiated tubular adenocarcinomas with tubulovillous adenoma. Pathological staging was pTis, pN0, M0, stage 0 according to the Japanese Classification of Colorectal Carcinoma (8th edition). It is now 6 months after the operation and hypokalemia has not recurred in the patient.