A 29-year-old man with von Recklinghausen's disease suddenly developed severe epigastric pain and was admitted to hospital. Physical examination revealed elevated blood pressure (200/130 mmHg) and tachycardia (162 bpm). Initially, he was suspected to have appendicitis, and appendectomy was performed immediately; however, appendicitis was not demonstrable pathologically. Retroperitoneal hematoma was found incidentally during the operation. Further clinical and laboratory examination demonstrated a marked increase in the urinary excretion of catecholamines. There was no evidence of pheochromocytoma on computed tomography or magnetic resonance imaging; however, these imaging studies simply showed a hematoma at the right adrenal gland. Transient hypertension and tachycardia, resembling pheochromocytoma, was caused by adrenal hemorrhage.