ABSTRACT Introduction McKittrick-Wheelock syndrome is a rare condition that arises from a hypersecretory state secondary to large colorectal tumors, mainly villous adenomas, leading to an electrolytic disorder associated with chronic diarrhea that usually persists for years. It is a relatively unknown disease that can lead to severe complications such as acute kidney injury, severe hyponatremia, and hypokalemia. In fact, it causes death in most untreated cases. Surgical removal of the tumor is the most successful treatment, and symptoms tend to disappear after proper management. Case Report A 62-year-old man with a 2-year history of mucoid diarrhea preceded by abdominal pain presented with acute kidney injury, hyponatremia, and hypokalemia. A digital rectal examination and sigmoidoscopy were performed, and revealed a large laterally-spreading tumor in the rectum. Further investigation showed a rectal tubulovillous adenoma with secondary McKittrick-Wheelock syndrome. An anterior resection of the rectum with a colonic J-pouch and a diverting ileostomy were performed, and the patient improved with the resolution of the renal failure and electrolyte disturbances. The histopathological analysis revealed an invasive rectal adenocarcinoma. Discussion McKittrick-Wheelock syndrome is a condition with a low incidence that needs early intervention and proper diagnosis. It is of extreme importance that this disease is included in the differential diagnoses for chronic diarrhea associated with an electrolytic disorder.
Abstract Introduction Most cases of colorectal cancer (CRC) occur sporadically; however, ~3% to 6% of all CRCs are related to inherited syndromes, such as Lynch syndrome and familial adenomatous polyposis (FAP). The adenomatous polyposis coli (APC) andmutY DNA glycosylase (MUTYH) germline mutations are the main genetic causes related to colorectal polyposis. Nevertheless, in many cases mutations in these genes have not been identified. The aim of the present case report is to describe a rare case of genetic colorectal polyposis associated with the axis inhibition protein 2 (AXIN2) gene. Case Report The first colonoscopy screening of a 61-year-old male patient with no known family history of CRC revealed ~ 50 colorectal polyps. A histological evaluation of the resected polyps showed low-grade tubular adenomas. Germline genetic testing through a multigene panel for cancer predisposition syndromes revealed a pathogenic variant in the AXIN2 gene. In addition to colorectal polyposis, the patient had mild features of ectodermal dysplasia: hypodontia, scant body hair, and onychodystrophy. Discussion The AXIN2 gene acts as a negative regulator of the Wnt/β -catenin signaling pathway, which participates in development processes and cellular homeostasis. Further studies are needed to support the surveillance recommendations for carriers of the AXIN2 pathogenic variant.