A Case of Secretory Diarrhea Caused by Giant Tubulovillous Adenoma (McKittrick-Wheelock Syndrome) Treated With Octreotide

Abstract

In patients with a history of colorectal neoplasm with refractory diarrhea causing dehydration, electrolyte disturbances, and/or renal failure, a rare condition called McKittrick-Wheelock syndrome must be considered. Early diagnosis is imperative as expedited resection of the culprit secretory adenoma may prevent progression to invasive malignancy. However, in patients who are poor surgical candidates, octreotide may be considered to palliate symptoms. A 70 year old male with history of colorectal cancer status post partial colectomy 13 years ago with no surveillance colonoscopies presented with 6 weeks of profuse, watery diarrhea refractory to loperamide. He denied any fever, nausea, abdominal pain, or new skin lesions. He denied any recent illness, antibiotic use, travel, sick contacts, or exotic food exposures. He was found to be hypotensive, dehydrated, and in acute renal failure. Initial workup was negative for infectious etiology. Abdominal ultrasound and CT scan of the abdomen and pelvis were unremarkable. His symptoms did not improve on empiric metronidazole, ciprofloxacin, rifaximin, loperamide, and atropine/diphenoxylate. Further workup revealed ESR 83 mm/hr, C-reactive protein 8.13 mg/dL, calprotectin 605 ug/g, and stool osmotic gap -2 mmol/L. He had negative calcitonin, gastrin, CEA, VIP, stool ova and parasites, HIV, tissue transglutaminase IgA, SPEP, and UPEP. Colonoscopy showed >20 polyps ranging 3-15mm and a 6cm tubulovillous adenoma (TVA) in the transverse colon. As he was a poor surgical candidate for definitive resection of his giant TVA and multiple polyps, he was started on octreotide with resolution of his diarrhea. Given the patient's giant TVA, secretory diarrhea, and metabolic derangements, he was diagnosed with McKittrick-Wheelock syndrome. Three percent of villous adenomas are secretory adenomas, which produce cyclic AMP, cyclooxygenase-2 (COX2), and prostaglandin E2 to cause secretory diarrhea. Definitive therapy is surgery to relieve symptoms and prevent invasive progression as up to 80% of these adenomas harbor adenocarcinoma. However, in patients who cannot undergo surgery, NSAIDs and somatostatin analogues have been proposed as nonsurgical alternatives. This unique case demonstrates that in patients with McKittrick-Wheelock syndrome who are poor surgical candidates, octreotide may be a suitable alternative to improve refractory diarrhea and the resulting dehydration, electrolyte disturbances, and renal failure.Figure: 6cm tubulovillous adenoma of the transverse colon.