Poorly Differentiated Neuroendocrine Tumor of the Rectum Coexistent with Giant Rectal Villous Adenoma Presenting as McKittrick-Wheelock Syndrome

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.

Lessons of the month 2: McKittrick-Wheelock syndrome: Case report of a patient declining resection of a large villous adenoma

McKittrick-Wheelock syndrome (MWS) is a rare cause of acute kidney injury and electrolyte depletion. It is driven by a secretory tumour or polyp of the distal large colon. Although rare, it is a diagnosis that must be considered in patients presenting with the above conditions. Treatment is with surgical resection of the offending growth. We present the case of a 70-year-old woman who presented multiple times with electrolyte depletion and acute kidney injury. The diagnosis of MWS was established and treatment options discussed. Surgical intervention was declined, and management consisted of patient education, the careful replacement of fluid and electrolytes and close monitoring of electrolytes and kidney function. After a short period as an inpatient, the patient went on to be discharged and, with regular follow-up, has managed to continue a normal life.

Giant villous adenoma of rectum- what is the malignant potential and what is the optimal treatment? A case and review of literature

INTRODUCTION

Villous adenomas are dubiously benign lesions, which are difficult to interpret because of their malignant potential. Distal villous adenomas present with bleeding or mucus discharge. Giant adenomas are not amenable for endoscopic or transanal resection. Only few isolated cases have been reported by laparoscopic resection. We present our case of a circumferential giant villous adenoma of the rectum managed successfully by laparoscopic ultra-low anterior resection with colo-anal anastomosis with a review of literature in regard to their malignant potential.

CASE REPORT

A 62-year-old lady presented with complaints of painless bleeding per rectum and a fleshy mass protruding from the anal canal which on digital rectal examination appeared a large soft velvety flat mass with mucus discharge. Colonoscopy showed circumferential irregular, friable, edematous mucosa in rectum extending for 15 cm. Computed tomography showed a large heterogeneously enhancing polypoid mass lesion in the rectal wall involving the entire rectum. The patient underwent laparoscopic low anterior resection with colo-anal anastomosis and protecting loop ileostomy. Histopathological examination of the resected specimen revealed villous adenoma of the rectum with moderate to severe dysplasia.

DISCUSSION

Villous adenomas are sessile growths lined by dysplastic glandular epithelium, whose risk of malignancy is especially high up to 50% when greater than 2 cm in size. Large size, villous content, and distal location are all associated with severe dysplasia in colorectal adenomas. Large villous rectal tumors, particularly of circumferential type pose a great challenge for endoscopic or transanal removal. Henceforth, open or laparoscopic surgery is required for these cases.

CONCLUSION

Giant rectal villous polyps are usually unresectable by endoscopic methods or transanal endoscopic microsurgery and are associated with a high rate of unsuspected cancer which requires a formal radical oncologic resection. As per current data, the combined risk of dysplasia/malignancy is about 83% with 50% risk of dysplasia and frank malignancy in 33% of cases of giant rectal villous adenomas of more than 8 cm in size. Laparoscopic colorectal resection is safe and effective.

McKittrick-Wheelock Syndrome Presenting with Acute Kidney Injury and Metabolic Alkalosis: Case Report and Narrative Review

A rare combination of severe volume depletion and electrolyte imbalance caused by a rectal villous adenoma is often referred to as the McKittrick-Wheelock syndrome. Patients usually seek medical care because of chronic hypersecretory diarrhea and display renal failure, metabolic acidosis, hyponatremia, and hypokalemia. We report the case of a 68-year-old woman who presented with this condition but showed unusual features such as severe hypokalemia and metabolic alkalosis, without diarrhea. She subsequently underwent transanal endoscopic microsurgery (TEMS), an innovative procedure in the management of large rectal adenomas. We also provide a narrative review of the literature on this rare entity.

A systematic review of McKittrick-Wheelock syndrome

INTRODUCTION

McKittrick-Wheelock syndrome describes the condition of extreme electrolyte and fluid depletion caused by large distal colorectal tumours, usually the benign villous adenoma. Patients generally present critically unwell with severe hyponatraemia, hypokalaemia and/or acute kidney injury.

METHODS

A structured literature review was undertaken to discover what is known about this condition, which is almost universally described as rare. Important features of the syndrome were identified, including common presenting symptoms, blood results, tumour location and size.

FINDINGS

Our literature search identified 257 cases reported across all languages. The most remarkable features were the long duration of symptoms (median 24 months) and the significant electrolyte derangements (median sodium of 122mmol/l and median potassium of 2.7mmol/l at initial presentation). Five key recommendations are made to improve diagnosis, including aggressive fluid resuscitation to match rectal losses and surgical intervention on the index admission. The advantages and disadvantages of different treatment options are discussed, including minimally invasive alternatives to traditional resectional surgery.

CONCLUSIONS

McKittrick-Wheelock syndrome describes a normally benign condition that can cause patients to become critically unwell and so it behoves all clinicians to be aware of it. By publishing recommendations based on a comprehensive literature review, we aim to improve diagnosis and management of this life threatening condition.

Malignant McKittrick-Wheelock syndrome as a cause of acute kidney injury and hypokalemia: Report of a case and review of literature

Colonic polyps are usually asymptomatic, and are commonly detected during screening colonoscopy. Severe hypokalemia secondary to secretory diarrhea is a rare presentation of rectal polyps. We present a 70 years old female with hypokalemia and acute kidney injury secondary to secretory diarhea due to moderately differentiated adenocarcinoma of rectum, all of which is syndromically sometimes referred to as McKittrick and Wheelock syndrome. The case is presented because McKittrick-Wheelock syndrome is still more uncommon with malignancy. The syndrome may be associated with other features of hypersecretory diarrhea. Though very rare, clinical suspicion would often lead to diagnosis and appropriate management. We also review the previously published reports of this entity.