[Slight hormonal alterations in a patient with a large pheochromocytoma]. / Mínimas alterações hormonais em paciente com grande feocromocitoma.

We present a case report that the patient had symptoms suggesting pheochromocytoma, a large tumor (> 50 g) and a single minimally altered laboratorial test, exemplifying a diagnostic pitfall. A 31 y.o. male patient had two acute abdominal events, the last one accompanied by headache, arterial hypertension, facial flushing, perspiration and cutaneous pallor. In another admission, the patient had sustained arterial hypertension and cardiac arrhythmia. From laboratory analysis, the vanililmandelic acid was slightly modified. Scintigraphy disclosed a large adrenal mass suggesting pheochromocytoma. Histopathology confirmed this hypothesis. This report points out that patients with symptoms suggesting pheochromocytoma, even when plasma catecholamines and urinary metanephrines levels are normal, may harbor large tumors with a high catecholamines turnover or that had undergone hemorrhagic necrosis.