Endocrine Abstracts

Background: Although pheochromocytoma is feared for its acute life-threatening complications, in some patients the symptoms can be subtle. This leads to delayed diagnosis and chronic morbidity. We report 2 cases who presented with long history of major gastrointestinal manifestations related to a pheochromocytoma Case 1: A 51-year-old female had severe constipation for 12 years. No bowel pathology was identified on ultrasonography, colonoscopy, colonic transit studies and isotope defecography. She had hypertension and poorly controlled diabetes. During a period of acute worsening, partial colectomy was planned but deferred as a preoperative CT scan identified left 4x3cm adrenal lesion and recent onset hypokalemia. Further investigations confirmed ACTH secreting- pheochromocytoma with a positive 68-Ga-DOTA scan. She had an uneventful left adrenalectomy, (histology confirming pheochromocytoma) with complete resolution of bowel symptoms and biochemical abnormalities. Case 2: A 50-year-old male presented with 12 years of severe constipation, anorexia, distention and weight loss. He had type-2 diabetes and resistant hypertension. Extensive bowel investigations were unremarkable, but an abdominal CT revealed 11x10cm heterogeneous right adrenal mass alongside features of bowel obstruction. Elevated urinary metanephrines confirmed pheochromocytoma and MIBG scan showed increased uptake. A few days prior to surgery, he presented with rapidly progressive congestive heart failure to which he unfortunately succumbed.

Discussion: Gastrointestinal pseudo-obstruction is rare and seen in 5-15% of patients of pheochromocytoma. The adrenergic effects of catecholamines can lead to severe gastrointestinal dysmotility, resistant to medical management. Bowel perforation is seen in 15% of these patients. Identifying the condition is important as surgeries performed with undiagnosed pheochromocytoma are associated with mortality close to 80%. Excision of pheochromocytoma is the most effective way of achieving resolution of bowel symptoms.

Conclusion: These cases underscore the need to consider pheochromocytoma in patients presenting with unexplained chronic severe gastrointestinal symptoms and an adrenal lesion.