FRI263 Challenges In Management Of Biochemically Silent Pheochromocytoma

Disclosure: G. Gannamani: None. T. Gourdin: None. J.K. Fernandes: None. Background: Incidental adrenal tumors are a common radiological finding. Biochemical work up is important as functioning adrenal tumors increase mortality and morbidity. Missing diagnosis of Pheochromocytoma can result in fatal outcomes. There have been case reports with asymptomatic and mildly elevated biochemical markers or symptomatic but no biochemical evidence which pose challenges in diagnosis. Here we describe a case of Metastatic Pheochromocytoma which was biochemically silent. Case Description: 61-year-old female with incidental finding of left adrenal mass measuring 8.7 x 5.6 x 5.7 cm on CT (Computed Tomography) scan for back pain 10 years prior to presentation. She was told no further testing was needed then as she was asymptomatic. She now has uncontrolled hypertension requiring multiple anti-hypertensives that prompted further work up. Biochemical work up at outside facility reported as normal aldosterone, renin activity, AM cortisol, ACTH, DHEA-S, plasma metanephrine and normetanephrine, epinephrine, norepinephrine, and dopamine. Elevated Chromogranin A of 5608 (normal < 93 ng/mL). Repeat CT Abdomen showed multiple enhancing lesions in liver, large lobulated adrenal mass measuring 15 x 10 x 14 cm (previously 8.7 x 5.6 x 5.7 cm) with central necrosis, absolute washout is 63%. This mass extended into gastro-hepatic space, obliterating fat space between the left adrenal mass and tail of pancreas was also reported. Imaging was concerning adrenal malignancy vs Pheochromocytoma. Further work up with MRI (Magnetic Resonance Imaging) Abdomen showed 14 cm centrally necrotic mass suggestive of adrenal neoplasm with loco-regional involvement. CT chest with bilateral pulmonary nodules and diffuse sclerotic and lucent bone lesions concerning osseous metastatic disease. Liver biopsy positive for metastatic neuroendocrine neoplasm consistent with Pheochromocytoma, immunohistochemical stains positive for Synaptophysin, Chromogranin, S100, GATA3, Inhibin. Dotatate PET CT with large centrally necrotic left adrenal mass. Abnormal radiotracer uptake in left kidney, stomach, gastrohepatic lymph nodes, widespread osseous lesions suggesting metastatic disease. She was not a surgical candidate given extension of mass and metastasis to multiple organs. Treatment started with Sunitinib (Tyrosine kinase inhibitor), plan to repeat imaging in 4-6 months hoping for tumor shrinkage. References: 1. Pheochromocytoma without specific symptoms. Jpn J Surg. 1984 May 2. A diagnostic dilemma in diagnosing and managing an incidental pheochromocytoma. Exp Clin Endocrinol Diabetes. 2006 Apr 3. Asymptomatic and Biochemically Silent Pheochromocytoma with Characteristic Findings on Imaging. Case Rep Endocrinol. 2020 Sep 26 Presentation: Friday, June 16, 2023