IS Case 196: Pheochromocytoma

Richard Gong, MD


Imaging Sciences URMC 2008
Publication Date: 2009-05-22

History

A 40-year-old female with history of neurofibromatosis had an abdomen and pelvis CT for fever and abdominal pain and a complex right adrenal mass was noted. Laboratories revealed elevated urine and serum normetanephrine levels.

Findings

Abdomen CT demonstrated a large heterogeneously enhancing mass in the right adrenal gland. Subsequent laboratories suggested pheochromocytoma and MR images demonstrated the classic light bulb appearance of the right adrenal pheochromocytoma.

Diagnosis

Pheochromocytoma

Discussion

Pheochromocytoma is a rare catecholamine-secreting tumor originating from the chromaffin cell in the adrenal gland. Extra-adrenal pheochromocytomas are termed paragangliomas. They reportedly occur in 0.05 to 0.2% of hypertensive individuals, but patients may be asymptomatic. Approximately 10% of pheochromocytomas are discovered incidentally. They can also occur in familial syndromes such as multiple endocrine neoplasia (MEN) 2A and 2B, neurofibromatosis and von Hippel-Lindau disease.

Symptomatic patients with pheochromocytoma have spells characterized by headache, palpitations and diaphoresis in association with severe hypertension. These spells vary in duration from seconds to hours and in frequency from monthly to several times a day. It is important to note that several factors have been reported as precipitants of a hypertensive crisis including anesthesia induction, radiographic contrast media, opiates, cold medications and childbirth.

Plasma metanephrine testing has the highest sensitivity (96%) and lower specificity for detecting a pheochromocytoma, while a 24-hour urine collection for metanephrines has a sensitivity of 87.5% and specificity of 99.7%. Imaging studies should only be performed after biochemical studies have confirmed the diagnosis of pheochromocytoma. MRI is preferred over CT and has sensitivity up to 100% in detecting pheochromocytomas.

Once discovered, the treatment of choice is surgical resection. Alpha blockade, followed by beta blockage is used preoperatively and during the surgery to prevent a hypertensive crisis.

References

  1. Sweeney AT, Blake MA, Melby JC. Pheochromocytoma. eMedicine, Sept. 11, 2007. http://emedicine.medscape.com/article/124059-overview
  2. Blake MA, Kalra MK, Maher MM, et al. Pheochromocytoma: an imaging chameleon. Radiographics. 2004 Oct;24 Suppl 1:S87-99. [PubMed]

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