McKittrick-Wheelock Syndrome Caused by Giant Tubulovillous Adenomas With Malignant Transformation: A Case Report.

Giant villous adenomas of the colon are a rare cause of chronic secretory diarrhea. These lesions can produce excessive mucus, fluid, and electrolyte loss, leading to life-threatening hypokalemia, hyponatremia, and acute kidney injury. Chronic secretory diarrhea with electrolyte imbalance and possible acute kidney injury caused by secretory giant tubulovillous adenomas constitutes McKittrick-Wheelock syndrome, a rare condition described in 257 patients worldwide. We report two cases of McKittrick-Wheelock syndrome caused by giant tubulovillous adenomas of the rectum and rectosigmoid junction with malignant transformation. The first case, a 72-year-old female, presented with profound electrolyte depletion and acute renal failure, managed in the intensive care unit with supportive therapy. The second case, a 73-year-old male, had chronic diarrheal syndrome and marked electrolyte depletion due to three giant colonic tubulovillous adenomas with malignant transformation. After rehydration and electrolyte replacement, both patients underwent surgical resection with low anterior rectal resection and protective loop ileostomy. The male patient required reoperation with total proctocolectomy due to coloanal anastomotic dehiscence. Postoperative courses were uneventful, and both patients were discharged with normalized laboratory values and scheduled for regular follow-up. McKittrick-Wheelock syndrome should be suspected in patients with chronic diarrhea and electrolyte disturbances. Prompt endoscopic evaluation allows accurate diagnosis, and timely fluid and electrolyte replacement combined with surgical resection of the secretory lesion is essential for effective treatment and prevention of serious complications.