Pheochromocytoma and hyperadrenocorticism in dogs: six cases (1982-1992).

Pheochromocytoma was diagnosed in 4 dogs with pituitary-dependent hyperadrenocorticism and 2 dogs with hyperadrenocorticism caused by adrenocortical tumor. All dogs were examined initially because of clinical signs associated with hyperadrenocorticism. Pheochromocytoma was suspected in 2 dogs with pituitary-dependent hyperadrenocorticism that had ultrasonographic evidence of an adrenal gland mass, and in 1 dog suspected to have hyperadrenocorticism associated with an adrenocortical tumor after complications (systemic hypertension, cardiac arrhythmias) developed during induction of anesthesia. Pheochromocytoma was an unexpected finding at necropsy in the remaining 3 dogs. Two dogs collapsed suddenly and died before diagnostic tests could be performed; the other dog died during anesthesia for cobalt teletherapy of a pituitary macroadenoma. Hypertension, most notable during digital manipulation of the affected adrenal gland, developed during anesthesia and surgery in 3 dogs that underwent exploratory celiotomy.