Adrenal pheochromocytomas: a broad spectrum of sonographic presentation

Sonographic findings in 19 patients with proved adrenal pheochromocytomas observed over a 10 year period were evaluated retrospectively. Adrenal tumors were analyzed by number, size, echogenicity, internal echogenicity, and biologic behavior. There were 16 benign and 3 malignant pheochromocytomas, all of which were well marginated or encapsulated and ranged from 1.4 to 11 cm in greatest diameter (mean, 4.8 +/- 2.2 cm). A broad spectrum of sonographic appearances has been noted, including purely solid tumors (68%), complex masses (16%), and cystic lesions (16%). Compared with renal parenchyma as a reference tissue, 10 (77%) of 13 solid pheochromocytomas were isoechoic or hypoechoic, whereas three (23%) were hyperechoic. Six (46%) of the solid tumors were homogeneously echogenic, and seven (54%) were heterogeneous. Ultrasonic discrimination between benign and malignant pheochromocytoma on the basis of acoustic features alone has proved impossible. Abdominal sonography, however, provided evidence of malignancy in all three patients with malignant tumors by disclosing regional or distant metastases. In conclusion, rather than showing a specific uniform ultrasonographic appearance, pheochromocytoma is associated with a broad spectrum of possible sonographic presentations.