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Pheochromocytoma

Pheochromocytoma

A 49-year-old man presents for a routine examination. He has a 15-year history of essential hypertension and a 7-year history of hypercholesterolemia and type 2 diabetes mellitus. The patient has lost 7.5 lb in the past 3 months. The physical examination
is remarkable for a blood pressure (BP) of 168/94 mm Hg and a palpable midline epigastric mass that is nontender, firm, and immobile.

Figure 1
Figure 1

Abdominal CT with contrast demonstrates an 87 × 116-mm necrotic, partially enhancing mass in the region of the left adrenal gland (Figure 1). Chest CT with contrast reveals multiple bilateral noncalcified pulmonary nodules with no other apparent lesions in the thorax.

The imaging findings prompt a laboratory evaluation of the adrenals with the following results: urine normetanephrines, 27,787 µg/24 h; total urine metanephrines, 27,861 µg/24 h; urine vanillylmandelic acid, 191.9 mg/24 h; urine norepinephrine,
5401 µg/24 h; and total calculated urine catecholamines, 5415 µg/24 h. Levels of urine dopamine and epinephrine are within
normal limits. A tumor marker workup reveals elevated levels of CA 125 (63 U/mL) and carcinoembryonic antigen (6.4 ng/mL). The radiographic findings and the significant elevation of catecholamines and their metabolites support a diagnosis of pheochromocytoma.

Figure 2
Figure 2

The patient undergoes a left adrenalectomy, left nephrectomy, and splenectomy. The cut surface of the 12-cm left adrenal mass reveals pale tan-gray tissue with central edema and fibrosis (Figure 2). The periphery of the lesion demonstrates prominent vasculature and nodularity. Intraoperatively, metastases are found in the left renal hilum and a periaortic
lymph node; these are resected.

Six weeks after the operation, laboratory results include the following: urine normetanephrines, 1388 µg/24 h; urine metanephrines, 1453 µg/24 h; urine norepinephrines, 371 µg/24 h; and total calculated urine catecholamines, 371 µg/24 h.
The level of urine dopamine is within normal limits, and the level of urine epinephrine is below the reportable range of 2 µg/24 h. The plasma chromogranin A level is 36 ng/mL. The BP and serum glucose level are normal.

Two months after the surgery, the patient undergoes a 123I-MIBG SPECT fusion scan, which shows no significant uptake in any of the pulmonary nodules. Consequently, he is not a candidate for high-dose 131I-MIBG therapy.

Recently, the patient's levels of catecholamines and their metabolites have begun to rise. This prompts radiologic reevaluation, which demonstrates an increase in the size of numerous pulmonary nodules and the presence of new pulmonary nodules
and a new paracaval adenopathy. These findings suggest a recurrence of malignant pheochromocytoma.

EPIDEMIOLOGY
Pheochromocytomas occur most commonly between the ages of 30 and 50 years. They are more prevalent in whites than in blacks
and somewhat more frequent in women than in men.1,2 The incidence is 1 per 2 million population.
Among persons with hypertension, 0.1% have an underlying chromaffin tumor as the primary cause.2

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