Teaching Case

50 years old - mild hypertension - adrenal mass- 24-hour urinary excretion of VMA :33 mg/24h.

50 years old woman with headache, epigastric pain and mild hypertension. Abdominal ultrasound was performed. In right adrenal location a well circumscribed mass was seen. Elevated 24-hour urinary excretion of VMA (33 mg/24h).

The diagnosis of pheochromocytoma is usually made on the basis of elevated catecholamine levels in serum or urine (VMA). Pheochromocytoma is a rare tumor of chromaffin cells most commonly arising from the adrenal medulla. The peak incidence is in the third to fifth decades of life. Bilateral disease is present in approximately 10% of patients. Approximately 10% of pheochromocytomas are considered to be malignant. There are no histologic features that distinguish benign from malignant tumors.Because the distinction between benign and malignant tumors cannot be made with certainty, careful surveillance is needed for a prolonged period after the initial surgical resection. Imaging is used primarily for localizing known tumors prior to surgery (Surgical resection is the standard curative modality). CT and MR imaging are equally accurate in diagnosing pheochromocytomas arising from the adrenal gland MR imaging was preferable to CT in the evaluation of primary pheochromocytomas due to superior tissue characterization and multiplanar capability. Adrenal pheochromocytomas tend to be large (2-5-cm) tumors and are highly vascular and rich in intracellular water. The tumors tend to be hypointense on T1-weighted MR images and are often described as markedly hyperintense on T2-weighted images. In a series of 45 pheochromocytomas in which MR imaging findings were compared with histopathologic findings, 60% of the lesions appeared very hyperintense on T2-weighted MR images.The majority of these lesions had intratumoral cystic regions at gross or microscopic pathologic examination, accounting for their appearance at T2-weighted imaging. Pheochromocytomas rapidly enhance with infusion of gadolinium-based contrast material.