Villous Adenomas of the Rectum and Sigmoid Colon with Severe Fluid and Electrolyte Depletion

Endoscopic Submucosal Dissection of a Giant Rectal Adenoma Manifesting as McKittrick-Wheelock Syndrome

McKittrick-Wheelock syndrome (MKWS) is an uncommon clinical manifestation of large, villous, epithelial lesions of the distal colon and rectum. Excessive secretion of electrolyte-rich mucus from these lesions leads to secretory diarrhea, electrolyte disorders and acute renal failure. Several cases of MKWS have been reported since its initial description in 1954. The definitive treatment for the great majority of MKWS cases has consisted of surgical resection of the affected part of the colorectum, usually in the form of a low anterior resection or an abdominoperineal resection with the formation of an ostomy. Recent developments in endoscopic resection techniques now offer new, minimally invasive treatment alternatives for MKWS patients. We present the first reported case in the Western world of MKWS caused by a rectal adenoma with a size of 19 × 10 cm, treated through endoscopic submucosal dissection. Through the lessons learned by this case, as well as by a thorough review of the literature, we discuss this uncommon syndrome, focusing on treatment alternatives.

The McKittrick-Wheelock syndrome: a rare cause of curable diabetes

McKittrick-Wheelock syndrome (MWS) is a rare consequence of severe dehydration and electrolyte depletion due to mucinous diarrhoea secondary to a rectosigmoid villous adenoma. Reported cases of MWS commonly describe hypersecretion of mucinous diarrhoea in association with dehydration, hypokalaemia, hyponatraemia, hypochloraemia and pre-renal azotemia. Hyperglycaemia and diabetes are rarely reported manifestations of MWS. Herein we describe the case of a 59-year-old woman who presented with new-onset diabetes and severe electrolyte derangement due to a giant rectal villous adenoma. Subsequent endoscopic resection of the tumour cured her diabetes and normalised electrolytes. This case describes a rare cause of 'curable diabetes' and indicates hyperaldosteronism and/or whole-body potassium stores as important regulators of insulin secretion and glucose homeostasis.

LEARNING POINTS

McKittrick-Wheelock syndrome (MWS) is typically characterised by the triad of pre-renal failure, electrolyte derangement and chronic diarrhoea resulting from a secretory colonic neoplasm.Hyperglycaemia and new-onset diabetes are rare clinical manifestations of MWS.Hyperaldosteronism and/or hypokalaemia may worsen glucose tolerance in MWS.Aggressive replacement of fluid and electrolytes is the mainstay of acute management, with definitive treatment and complete reversal of the metabolic abnormalities being achieved by endoscopic or surgical resection of the neoplasm.

Giant rectal villous adenoma: Surgical approach with rectal eversion and perianal coloanal anastomosis

INTRODUCTION

Colorectal cancer is an important cause of death. Most cases of colon and rectal cancer arise from a preexisting adenomatous polyp. However, if colorectal polyps are very large or not accessible for endoscopic ablation, or if they cannot be removed without an increased risk of perforation, surgical procedures are required.

PRESENTATION OF CASE

The case of a patient with a giant villous adenoma of the rectum is described. The patient had diarrhea for 2 years associated with asthenia. Colonoscopy revealed a sessile lesion in the rectum measuring 14cm in the largest diameter. Rectal eversion technique was used, resecting the lesion under direct visibility and an external coloanal anastomosis was performed. Surgery was satisfactory and the resection margins were free.

DISCUSSION

Removal of these polyps should be performed aiming to reduce the incidence of colorectal cancer, as well as to control local and systemic symptoms, such as diarrhea and fluid and electrolyte disorders, mainly in villous adenomas. Various surgical techniques are proposed, but in extensive circumferential lesions of the rectum they are difficult to apply. The rectal stump eversion technique was described by Maunsell (1892), for rectal cancer.

CONCLUSION

Eversion of the rectal stump and external coloanal anastomosis may be a good surgical alternative for resecting giant rectal adenomas.

Pathophysiology of potassium absorption and secretion by the human intestine

When normal people ingest 90 mEq/day of K+ in their diet, they absorb about 90% of intake (81 mEq) and excrete an equivalent amount of K+ in the urine. Normal fecal K+ excretion averages about 9 mEq/day. The vast majority of intestinal K+ absorption occurs in the small intestine; the contribution of the normal colon to net K+ absorption and secretion is trivial. K+ is absorbed or secreted mainly by passive mechanisms; the rectum and perhaps the sigmoid colon have the capacity to actively secrete K+, but the quantitative and physiological significance of this active secretion is uncertain. Hyperaldosteronism increases fecal K+ excretion by about 3 mEq/day in people with otherwise normal intestinal tracts. Cation exchange resin by mouth can increase fecal K+ excretion to 40 mEq/day. The absorptive mechanisms of K+ are not disturbed by diarrhea per se, but fecal K+ losses are increased in diarrheal diseases by unabsorbed anions (which obligate K+), by electrochemical gradients secondary to active chloride secretion, and probably by secondary hyperaldosteronism. In diarrhea, total body K+ can be reduced by two mechanisms: loss of muscle mass because of malnutrition and reduced net absorption of K+; only the latter causes hypokalemia. Balance studies in patients with diarrhea are exceedingly rare, but available data emphasize an important role for dietary K+ intake, renal K+ excretion, and fecal K+ losses in determining whether or not a patient develops hypokalemia. The paradoxical negative K+ balance induced by ureterosigmoid anastomosis is described. The concept that fecal K+ excretion is markedly elevated in patients with uremia as an intestinal adaptation to prevent hyperkalemia is analyzed; we conclude that the data do not convincingly show the existence of a major intestinal adaptive response to chronic renal failure.

Management of benign villous adenomas of the entire rectum

While villous adenomas of the rectum are common, they rarely encompass the entire rectum to the dentate line. It is even more unusual to find a tumor of this size to be benign. Fluid and electrolyte deficits associated with this tumor add to the difficulty in management. The experienced surgeon should be aware of the various modes of treatment and be able safely to use the appropriate operation. It is as grave an injustice to the patient to treat a benign lesion as a malignancy as it is to remove the rectum for a benign villous adenoma.

Villous adenoma with hyponatremia and syncope: report of a case

A case of villous adenoma of the colon with hyponatremia, hypovolemia, and syncope is presented. The correct diagnosis was delayed because of the prevailing idea that villous adenomas are associated with hypokalemia. The patient recovered fully after surgical removal of one of the largest villous adenomas reported in the literature. Sodium loss may be the dominant feature of this syndrome. Villous adenoma has to be included among the causes of hyponatremia.

Villous adenoma of the colon with severe fluid and electrolyte depletion: report of a case

A case of severe fluid and electrolyte depletion resulting from a massive villous adenoma of the rectosigmoid colon is presented. The syndrome is discussed, and the often insidious presentation and life-threatening aspects are emphasized.

Villous adenomas of the colorectum

During a ten-year period 258 patients with villous adenomas were seen at the Massachusetts General Hospital: seventy-four of these patients (29%) had invasive cancer that developed in adenomas. The operative mortality ascribed to removal of benign adenomas was zero, but for cancer arising in villous adenomas it was 3 per cent. Therapy often is difficult because of the size and location of the tumors. Methods of removal have been considered in detail.

Villous adenomas of the colon and rectum

Our thirteen year experience with villous adenomas of the colon and rectum, embracing 264 patients, is reported. The average age of patients was sixty-two years with an almost equal sex distribution. Seventy-two per cent of the lesions occurred in the rectum and rectosigmoid and the most frequent symptoms were rectal bleeding and diarrhea. A positive correlation between size of adenoma and incidence of malignancy was noted. Although 55 per cent of the lesions were malignant, only 22 per cent harbored invasive carcinoma and only 10 per cent of the deaths were due to metastatic carcinoma. It is concluded that in the absence of invasive carcinoma, the clinical behavior of this tumor is relatively benign and a more conservative approach to the surgical management of this neoplasm should be encouraged.

Papillary adenomas of the colon and rectum: a twelve-year review

During a 12-year period, 185 patients with papillary adenomas of the colon and rectum were treated. The average age was 63 years and there was a 10 per cent female preponderance. Seventy-one per cent of the lesions occurred in the rectum and rectosigmoid, and 40 per cent of the patients had rectal bleeding. Fifty-two per cent of the lesions were malignant: however, only 9 per cent of the patients died with metastatic carcinoma. The five-year survival rate in patients with papillary adenocarcinoma was 75 per cent. The results of this review indicate that a conservative approach to the surgical management of papillary adenoma of the colon and rectum should be encouraged, unless the tumor contains or is suspected to contain invasive carcinoma.

Villous adenoma of the colon and rectum: an ultrastructural study

The villous component of nine colonic polyps (three pure villous adenoma and six mixed adenomatous and villous adenomas) was studied by light and electron microscopy. Normal colonic mucosa was used for control. The predominant cell was an undifferentiated epithelial cell resembling those of the base of the crypts of normal colonic mucosa. A minority of these cells differentiated toward goblet cells and absorptive cells. Interdigitations of the plasma membrane with enlarged intercellular spaces were frequently observed, possibly related to the loss of water and electrolytes in some of these tumors, suggesting an analogy to renal tubular plasma membrane changes in kalliopenic nephropathy. Numerous membrane-bound, inter and intracellular "inclusion bodies" representing degenerated lymphocytes and epithelial cell organelles were commonly found. Viral inclusions were not detected in this material. The possibility that the inclusion bodies observed in villous adenoma may represent lysosome-modified vesicles, secondary to absorption of protein and surface mucosubstances appears unlikely.

Villous papilloma of the rectum (with unusual complications)

A case is reported in which a villous papilloma of the rectum was complicated by severe electrolyte losses and acute renal failure. Successful management by peritoneal dialysis and early surgery is described.

Villous papillomata of the large bowel associated with renal failure

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A MUCUS-SECRETING VILLOUS ADENOMA OF THE RECTUM

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THE ABSORPTION OF WATER, SODIUM, AND POTASSIUM IN THE LARGE INTESTINE WITH PARTICULAR REFERENCE TO THE EFFECTS OF VILLOUS PAPILLOMAS

The absorption of water, sodium, and potassium from isolated segments of the large intestine has been studied in 11 patients. In eight control segments adjacent to a carcinoma of the colon, absorption of water and sodium and secretion of potassium occurred. In five segments of intestine containing a villous papilloma, water, sodium, and potassium were secreted. The difference is mainly due to an increase in exsorption of sodium and water, insorption being relatively unaffected.