Use of ¹²³iodine Metaiodobenzylguanidine Scintigraphy for the Diagnosis of a Pheochromocytoma in a Dog

A 13‐year‐old neutered female Yorkshire terrier presented with a history of progressive episodic weakness and disorientation of 4 months duration. Physical and neurologic examinations were normal at presentation. Abdominal ultrasound revealed a mass involving the right adrenal gland. Standard planar scintigraphy was performed at 4, 18, and 24 hours after intravenous injection 185 MBq (5mCi) of 123 I‐labeled metaiodobenzylguanidine ( 123 I‐MIBG). An area of focal intense uptake was identified in the area of the right adrenal gland. A pheochromocytoma was confirmed histologically after surgical excision.