A Tale of Two Cities: Do They Have the Same Destination: Asymptomatic Pheochromocytomas: Biochemically Functioning vs Non Functioning

Abstract

Background: Pheochromocytomas (PHEOs) are enterochromaffin tumors arising from the adrenal gland. Their diagnosis and preoperative preparation is crucial due to high morbidity and mortality rates with unrecognized, undiagnosed PHEOs. Case 1: 62-year-old male with a medical history of HCC, noted to have right adrenal adenoma measuring 1.7 x 1.6 cm. Denied any symptoms and normotensive on exam. A PET scan done showed a hypermetabolic right adrenal nodule concerning for malignancy. Serum metanephrines were 45 pg/ml (nl <57 pg/ml) and total plasma metanephrines were 172 pg/ml (nl <205 pg/ml). A CT guided biopsy was consistent with a PHEO. Other labs included: 24 hour urine metanephrines: 155 mcg (nl 90–315), total metanephrines: 520 (nl 224–832) and vanillylmandelic acid was 3.6 (nl <6.0). 24-hour urine epinephrine: 10 mcg (nl 2–24), norepinephrine:57 mcg (nl 15–100) and dopamine: 421 (normal 52–480). Case 2: 55 year old male with UTI and flank discomfort, noted to have incidental 8cm Right adrenal mass noted concerning for malignancy. Also denied any symptoms and normotensive. Plasma fractionated metanephrines 938 (ref <206), metanephrine 279,Normetanephrine 659(ref <148), 24 hr urine metanephrines=1176mcg/24 hr (90–315), Normetanephrines 1487 (122–676), 24 hr urine total metanephrines 2663 (224–832). He is refusing α and β blockade due to normotension in preparation for surgery. Discussion: It is important to suspect, confirm, localize, treat, and PHEOs for several reasons. Most of these tumors hypersecrete catecholamines, and if untreated, cardiovascular morbidity and mortality are high. Another reason to encourage case detection is that, for familial disease, detection of a tumor in the proband may result in earlier diagnosis and treatment in other family members. Alpha-blockade is usually used prior to resection of Pheochromocytomas. However, the data available in the literature regarding alpha blockade for “truly asymptomatic” functioning or non functioning Pheochromocytomas is scarce. However what is unique to our cases is that they both are normotensive and asymptomatic and refusing preoperative preparation. Conclusion: Asymptomatic PHEO are becoming more common presentation given Pheochromocytomas are rare. Are the genetics and biochemical nature any different than classic pheos? Are we supposed to manage them the same way? Would we rethink current guidelines for managing normotensive or nonfunctioning pheochromocytomas pre operatively? We also would like guidelines on how to prepare such truly asymptomatic patients prior to surgery. We refer to Endocrine Society guidelines for management of such tumors.