Introduction The uncommon McKittrick-Wheelock syndrome is characterized by hypersecretion of fluids and electrolytes by large rectal villous adenomas. Untreated disease may cause fatal renal insufficiency or arrhythmia. We report two cases with a different presentation. Case description Patient A, an 83-year old female with longstanding renal insufficiency of unknown origin presented with dehydration and recurrent collapse. Laboratory examination revealed hyponatremia, hypokalemia and renal insufficiency, and the patient was admitted for fluid resuscitation. A subsequent thorough history revealed longstanding diarrhoea, which deteriorated during the 5 days prior to admission. Colonoscopy was performed and revealed a very large rectal adenoma of 9 cm in diameter, covering 75% of the rectal circumference. There were no endoscopic signs of submucosal invasion. The adenoma was removed by endoscopic piecemeal resection during a 3.5 hour procedure. Her electrolytes normalized entirely thereafter. Despite an excellent clinical condition, a rectal stenosis (a common complication of extensive mucosal resection) demanded endoscopic dilatation. Endoscopic resection of recurrent adenomatous tissue was hampered by the stenosis after 9 months. She was subsequently referred for resection via transanal endoscopic microsurgery (TEM). This procedure was uneventful; the patient is currently free of complaints. Patient B, a 66-year old diabetic male, presented with malaise, fatigue and weight loss since 7 months. Physical examination showed a tender right upper abdominal quadrant without any palpable masses. Rectal digital examination did not reveal any abnormalities. Laboratory examination showed severe renal insufficiency. Abdominal ultrasound revealed a large mass in the rectum. No distant metastases were seen on a CT-scan. During subsequent colonoscopy, a giant rectal adenoma was found, extending from the anorectal verge to 10 cm proximally. Piecemeal endoscopic mucosal resection was attempted and after 5 hours, 80% of the adenoma was removed. His renal function and electrolyte levels recuperated entirely thereafter. In a second session, a fibrotic area within the adenoma remnants could not be resected endoscopically and demanded surgical treatment via transanal endoscopic microsurgery. The specimen contained submucosally invasive carcinoma. Conclusion Renal insufficiency and electrolyte imbalance may sometimes be caused by large rectal adenomas. McKittrick- Wheelock syndrome is a relatively unknown, yet curable disease with potential fatal complications. Presenting symptoms are in concordance with electrolyte imbalances; diarrhoea is not necessarily a prominent complaint. Diagnosis is only possible by endoscopy. Curative endoscopic or surgical removal of the adenoma is complex and should only be performed in centres with sufficient expertise.
Hsieh, M. C., Chen, C. J., & Huang, W. S. (2016). McKittrick-Wheelock Syndrome. Clinical Gastroenterology and Hepatology, 14(4), e41–e42. https://doi.org/10.1016/j.cgh.2015.09.001