A 73-year-old woman with no remarkable medical history was admitted to our institution because of a 4-week course of recurrent episodes of dizziness, uncontrolled hypertension, and weight loss. Crises were stereotypical, beginning with headache, hot flush, profuse sweating, and quadriparesthesia followed by an increase in blood pressure and spontaneous resolution after 5 to 10 minutes. The results of a clinical examination after the episodes had subsided were normal. Suspicion of pheochromocytoma was supported by a large increase in norepinephrine levels in both serum and urine samples (serum norepinephrine, 14479 nmol/L [normal range, 1182-1773 nmol/L]; urinary norepinephrine, 1217.5 µmol per gram of creatinine [normal range, <532 µmol per gram of creatinine] [for 1 day]; urinary normetanephrine, 15937 µmol per gram of creatinine [normal range, <4200 µmol per gram of creatinine] [for 1 day]). There was no significant increase in either serum epinephrine or serotonin levels or urinary metanephrine and 5-hydroxyindoleacetic acid levels. Plasma levels of calcium, vasoactive intestinal polypeptide, gastrin, and calcitonin were also normal. Chest radiography showed a nodule (3-cm diameter) in the upper portion of the right lobe. A body computed tomographic scan and cerebral and medullar magnetic resonance imaging found no other localization of the tumor. Surprisingly, metaiodobenzylguanidine scintigraphy found no fixation, even in the lung. Before undergoing a surgical resection of her tumor, the patient died in a clinical episode of acute bowel occlusion. The autopsy revealed a lung bronchiolo-alveolar carcinoma with carcinomatous meningitis but no cerebral involvement. The tumor had no neuroendocrine differentiated cells since it was negative for neuron-specific enolase and chromogranin. Moreover, a meticulous examination of all the organs found no evidence of a neuroendocrine tumor, in keeping with the metaiodobenzylguanidine scintigraphy results. The cause of death could not be determined.