The Cystic Pheochromocytoma

As pheochromocytomas enlarge, they develop areas of hemorrhagic necrosis. Most pheochromocytomas >4 cm in diameter have some cystic component that is evident on computed cross-sectional imaging. Some pheochromocytomas become progressively cystic to the point that the radiologist interprets them as adrenal cysts. Such a case is reported herein.

Case Report

The patient was a 50-year-old woman who presented with persistent and recurrent emesis that led to abdominal computed tomography (CT). Incidentally discovered on the CT scan was a 7 × 8.3–cm cystic right adrenal mass ( Fig. 43.1 ). The patient was morbidly obese (body mass index 51.6 kg/m ² ). She had well-controlled hypertension of 7 years, duration that was treated with a β-adrenergic blocker (atenolol 100 mg daily) and an angiotensin receptor antagonist (valsartan 80 mg daily). She also had type 2 diabetes mellitus diagnosed 5 years previously and treated with metformin 500 mg once daily. Her blood pressure was 136/76 mmHg and heart rate was 76 beats per minute.

INVESTIGATIONS

The plasma fractionated metanephrines and 24-hour urine for fractionated metanephrines and catecholamines unequivocally confirmed the diagnosis of pheochromocytoma ( Table 43.1 ).

TABLE 43.1

Laboratory Tests

Biochemical Test	Result	Reference Range
Sodium, mmol/L	141	135–145
Potassium, mmol/L	4.0	3.6–5.2
Creatinine, mg/dL	0.8	0.6–1.04
Glycosylated hemoglobin, %	7.0	4.2–5.6
Plasma metanephrine, nmol/L	1.1	<0.5
Plasma normetanephrine, nmol/L	14.0	<0.9
Aldosterone, ng/dL	10	≤21 ng/dL
Plasma renin activity ng/mL per hour	14	≤0.6–3
24-Hour urine:
Metanephrine, mcg	1022	<400
Normetanephrine, mcg	6761	<900
Norepinephrine, mcg	239	<80
Epinephrine, mcg	9.1	<20
Dopamine, mcg	219	<400