SAT-484 Incidental Pheochromocytoma with Concurrent Adrenal Metastasis from Non-Small Cell Lung Cancer A Rare Presentation

Abstract Disclosure: S. Kafle: None. M. Upadhyay: None. K. Bhusal: None. B.R. Ellison: None. Clinical Case Report: Pheochromocytoma is a catecholamine-secreting tumor arising from chromaffin cells of the adrenal medulla. While most cases are functional, a subset remains asymptomatic, posing diagnostic challenges. Here, we present a rare case of an incidentally discovered pheochromocytoma in a patient with non-small cell lung carcinoma (NSCLC) and concurrent adrenal metastasis.She is a 66-year-old female with a history of NSCLC underwent two left adrenal biopsies, both yielding benign results. Computed tomography (CT) of the abdomen revealed a 2.1 cm left adrenal nodule with a pre-contrast Hounsfield unit (HU) of 32 and an absolute washout of 55.6%. Positron emission tomography (PET) imaging demonstrated hypermetabolic activity in the right upper lobe lung nodule, a hypermetabolic left adrenal gland nodule, and an additional focus in the descending colon. She was asymptomatic for pheochromocytoma. Given concerns for adrenal metastasis, the multidisciplinary team proceeded with a left adrenalectomy.Preoperative biochemical evaluation, including plasma metanephrines (measured twice), cortisol, renin, and aldosterone, was within normal limits. However, during surgery, the patient experienced severe hypotension and tachycardia, raising intraoperative suspicion for an occult pheochromocytoma. This crisis was managed with vasopressors and intravenous fluids. Histopathological analysis confirmed the presence of pheochromocytoma alongside metastatic adenocarcinoma. Discussion: Although most pheochromocytomas are functional, approximately 10% are non-functional, making diagnosis challenging. The classic triad of headaches, sweating, and tachycardia may not always be present, and biochemical markers can be normal if samples are not collected during catecholaminergic surges.Despite normal biochemical tests preoperatively, this case emphasizes the need for preoperative optimization, to prevent life-threatening hemodynamic instability. Furthermore, the concept of cyclical pheochromocytoma, where biochemical markers intermittently normalize, should be considered during surgical planning. A high index of suspicion and a multidisciplinary approach are critical for optimal patient management. Conclusion: This case highlights the diagnostic and perioperative challenges of pheochromocytoma in adrenal masses, particularly in asymptomatic patients with normal biochemical evaluations. The coexistence of pheochromocytoma and adrenal metastasis from NSCLC underscores the importance of comprehensive preoperative evaluation and multidisciplinary coordination to ensure safe surgical outcomes. Early recognition and management of pheochromocytoma, even in the absence of classic symptoms, are crucial to minimize the risk of complications. Presentation: Saturday, July 12, 2025