IN 1950, almost 30 years after the first description of pheochromocytoma, Smithwick1was able to collect only 270 cases from the literature. Since then an ever increasing number of cases has been reported, indicating a growing awareness of this disease. Many excellent reviews have pointed out the diagnostic difficulties so frequently encountered. A case of pheochromocytoma recently observed in a patient with chronic acromegaly should serve to demonstrate a few of these diagnostic difficulties. In addition, the combination of pheochromocytoma with chronic pituitary adenoma may stimulate some etiological considerations. Report of a Case In 1944, a 23-year-old white male developed signs and symptoms of acromegaly. In 1945, enlargement and erosion of the sella turcica were noted on x-rays, characteristic visual field defects were found, and the patient received radiation therapy for a pituitary adenoma. Thirteen years later, in April and in June, 1960, he had two brief episodes of