7564 Adrenal Pheochromocytoma In A Clinically Inapparent Adrenal Mass

Abstract Disclosure: L. Medina Mora: None. S. Htoo: None. A. Sanchez Ruiz: None. M. Harshan: None. A. Busta: None. Introduction: Pheochromocytomas (PCC) are rare tumors that arise from the adrenal medulla, with an estimated annual incidence of 0.8 per 100,000 person-years. These tumors have been associated with significant morbidity and mortality and are considered among the most life-threatening endocrine diseases, particularly if left undiagnosed. Its symptoms can be related to the tumor's mass effect or catecholamine excess. As a result, they can mimic other conditions, often leading to delayed or incorrect diagnosis. A study conducted on 296 patients with PCC treated from 2005 to 2016 found that 61% were discovered incidentally through cross-sectional imaging (CSI). The widespread use of CSI in recent years has led to the identification of asymptomatic cases that would have otherwise gone undetected. In this case, we present a middle-aged female who was incidentally found to have a PCC. Case Report: A 59-year-old female with a history of hypertension, cerebrovascular accident, pulmonary hypertension, systolic heart failure, mitral valve replacement, and asthma presented to the clinic for evaluation of a right adrenal lesion measuring 4.2 x 3.5 cm found during an emergency room visit during the evaluation of chest pain. She had no known family history of brain or endocrine disorders. Her lab results showed elevated plasma metanephrine and normetanephrine to 578.4 (reference range: 0-88) and 459.9 (reference: 0-244), respectively. Additionally, her 24-hour urine metanephrine was elevated to 984 mcg (normal range: 36-209), and Chromogranin A was 164.3 (reference range: 0-101). The rest of her labs, including cortisol, renin, aldosterone, and DHEA-S were unremarkable. A CT with and without contrast revealed a 3.0 x 3.5 x 5.1 cm solid non-calcified right adrenal mass measuring 39 Hounsfield units (HU). In addition, it measured 53 HU in the venous phase and 61 HU in the 15-minute delayed phase (relative washout of 1%; absolute washout of 7%). The patient was treated with alpha-blockers and underwent a robotic-assisted right adrenalectomy. The pathology was significant for a 5.4 cm well-differentiated PCC. The tumor had extended into but not beyond the adrenal capsule. The postoperative course of the patient was uncomplicated. Discussion: After a PCC is detected, the most effective treatment option is to surgically remove it. This procedure necessitates a combination of alpha and beta-blockade to regulate blood pressure and prevent a hypertensive crisis. Despite the success of surgery, there is still uncertainty about the optimal follow-up after the procedure, which often leads to many patients being lost during the process. Furthermore, even a decade after the initial surgery, there remains a substantial likelihood of illness reoccurrence or metastasis, making the situation even more complex. Therefore, it is crucial to adhere to a lifelong follow-up plan that includes annual biochemical testing. Presentation: 6/2/2024