Endocrine Abstracts

Introduction: Classically, hypertension (sustained or paroxysmal) is described in > 98% of diagnosed pheochromocytomas. Nowadays the systematic workup of adrenal incidentalomas has made uncovering normotensive pheochromocytomas no longer exceptional. However, normotensive pheochromocytomas have a catecholamine secretion characteristically lower than hypertensive pheochromocytomas. It must be emphasized that the perioperative hemodynamic instability is comparable in hypertensive and normotensive pheochromocytomas, and much higher than in non-pheochromocytoma adrenal masses.

Clinical case: After caustic ingestion, a 53-year-old male patient suffered extensive gastric ulcers and pyloric stenosis. He was referred to our Endocrinology Clinic because in a CT scan a dense heterogeneous mass measuring 4.4x4.6 cm with gross calcifications and lobulated outline was incidentally found in the right adrenal. The patient was asymptomatic, normotensive, had no medication except pantoprazol, and reported no history of hypokalemia, headaches or hypertensive crisis. The physical exam was unremarkable, with height 179 cm, weight 73 kg, BP 126/81 mmHg, HR 68 lpm. There were no signs of Cushing’s syndrome. Glucose, creatinine and eGFR, ions, lipids, transaminases, GGT, blood count, TSH, cortisol, ACTH, LH, FSH and testosterone were normal. Fasting cortisol was 14.4 μg/dL, aldosterone 10.3 ng/dl, PRA 1.1 ng/ml/h, ratio A/PRA 9.4 (normal). Unexpectedly, plasma metanephrine was 35 pg/ml (normal), normetanephrine 2264 pg/ml (UNL 196), and cromogranin A 361.5 ng/ml (UNL 100) with 24 h urinary metanephrine 264 μg (normal) and normetanephrine 1656 μg (UNL 444). A MIBG/SPECT CT scan showed a right adrenal pheocromocytoma without additional lesions. 24 h ABPM was performed in order to confirm normotension. Awake BP was 128/75 mmHg with HR 81 lpm, sleep BP was 115/64 mmHg with HR 69 lpm, with normal dipper pattern, but there was an unexplained BP peak (159/84 mmHg) at 16:00. The patient is at present ready for right laparoscopic adrenectomy, having started treatment with doxazosin 4 mg bid followed by bisoprolol 10 mg bid, adequate hydration and ClNa supplements 6 g/24 h, with mild hypotensive symptoms.

Conclusions: We certainly would expect a patient with such a large epinephrine output to be hypertensive, but have no explanation why it was not the case. The workup of adrenal incidentalomas must include screening for pheochromocytoma even in normotensive patients. In order to prevent perioperative hemodynamic instability, patients with normotensive or hypertensive pheochromocytoma need the same preparation (including adrenergic blockade, hydration and salt supplementation) although it might elicit symptomatic hypotension.