McKittrick-Wheelock Syndrome: A Rare Cause of Diarrhea in a Young Woman

Abstract

Tubulovillous adenomas account for 5% of all adenomas and have a higher incidence of becoming malignant than tubular adenomas. Larger lesions can also lead to obstruction and hypersecretory complications. McKittrick-Wheelock Syndrome is a rare cause of secretory diarrhea from a rectosigmoid villous adenoma generally >4 cm in size that can lead to severe electrolyte derangements, dehydration, renal failure, and even death. We present a rare case of McKittrick-Wheelock Syndrome in a young, pregnant woman. A 26 year old Hispanic woman in her first trimester of pregnancy presented to outside hospital with diarrhea and weight loss, initially treated conservatively. Over the next month she developed large volume mucoid diarrhea with hypotension and electrolyte abnormalities (Na 120 mmol/L, K 1.8 mmol/L) requiring IV hydration and up to 300 mEq/L of KCl supplementation per day. Sigmoidoscopy revealed a large obstructing rectal mass 8 cm from the anal verge. Cold forcep biopsies showed villous adenoma. Due to the obstructive nature of the mass, at week 19 of her pregnancy she underwent an open diverting transverse colostomy and was transferred to our institution for definitive management. MRI showed a large pedunculated mass extending from the anal verge, filling the lumen to 11 cm proximally with rectal thickening (figure 1, 2). Repeat colonoscopy showed a friable circumferential gelatinous mass from the anal verge to 15 cm (figure 3) with biopsies consistent with villous adenoma with low grade dysplasia; there were no synchronous lesions. She was diagnosed with McKittrick-Wheelock Syndrome with plan for definitive surgical resection post-partum. She remained hospitalized throughout her pregnancy and delivered successfully via C-section at 37 weeks. At 5 weeks post-partum she underwent low anterior resection of the rectal tumor which revealed a 13.2 cm secretory villous adenoma without high grade dysplasia. Within 1 week her mucoid rectal discharge ceased and her electrolytes stabilized. McKittrick-Wheelock Syndrome is a rare cause of secretory diarrhea. These lesions consist primarily of mucin-secreting goblet cells that secrete water and electrolytes; larger lesions entail a greater surface area that when in the distal-most portion of the colon limit the ability to absorb fluid. Hypersecretory rectosigmoid villous adenoma should be in the differential in patients with unexplained secretory diarrhea, and prompt diagnosis and early resection is prudent.Figure 1Figure 2Figure 3