7783 Pheochromocytoma Unusually Presenting As Intestinal Pseudo-Obstruction: A Case Report

Abstract Disclosure: J.V. Chua: None. E.C. Cunanan: None. J.G. Sazon: None. J.L. Reyes: None. Introduction: Pheochromocytoma is a rare neuroendocrine tumor that arises from the adrenal medulla. It may present with a variety of symptoms that can resemble other diseases as a result of the effects of catecholamine overproduction on the different organ systems of the body, occasionally making diagnosis difficult and delaying appropriate treatment.Intestinal pseudo-obstruction is an unusual presentation of pheochromocytoma from the effects of excessive catecholamines on the gastrointestinal system, resulting in decreased peristalsis with constriction of the sphincter muscles, consequently prolonging intestinal transit time. Currently, there is no available data on its incidence or prevalence rate. Clinical Case: This is a case of a 50-year-old Filipino male initially presenting with abdominal pain and enlargement with inability to pass stool and flatus, not relieved by laxatives, enemas, and nasogastric and rectal tube decompression. Abdominal radiograph revealed segmental ileus versus partial large bowel obstruction, while abdominal CT scan showed fecal impaction and an incidental finding of an enhancing adrenal mass on the left adrenal gland. Colonoscopy findings were unremarkable. Laboratory workup demonstrated elevated 24-hour urine metanephrine levels with a value of 44.62 mg/24 hours (normal value: 0-1.0 mg/24 hours). The patient was initially managed conservatively, but no improvement in symptoms was noted. Pre-operative preparation was done with terazosin and intravenous saline infusion, and the patient then underwent left open adrenalectomy with bowel decompression, which provided resolution of symptoms and resumption of regular bowel movement post-operatively. The final result of the histopathologic examination confirmed the diagnosis of pheochromocytoma. Conclusion: Gastrointestinal symptoms such as ileus and pseudo-intestinal obstruction are uncommon presentations of pheochromocytoma. A high index of suspicion is necessary among patients presenting with these symptoms, and pheochromocytoma should be considered as part of the differential diagnosis. Presentation: 6/1/2024