Diagnostic imaging in canine pheochromocytoma

The diagnosis of pheochromocytoma is challenging due to the variable presen tations of patients affected with this neoplasm. This report describes four dogs with pheochromocytoma in which radiography, ultrasonography and compu ted tomography (CT) were key diagnostic tools. Computed tomography was the most useful imaging modality for assessment of size, shape and margination of the tumor. CT findings for the pheochromocytoma included a large, irregu larly shaped mass in the dorsal midabdomen with multiple foci of low attenu ation dispersed in hyperdense, highly vascular tissue. This neoplasm often invades the caudal vena cava and other surrounding organs therefore, althou gh a pheochromocytoma may be identified in the absence of clinical signs, i t should not be considered an incidental lesion. The unpredictable growth r ate and potential for invasion of major vessels warrants serious considerat ion. Follow-up ultrasound and CT examinations are recommended for patients with adrenal masses that do not undergo surgical excision.