Observed differences between brindle and fawn Boxers with pituitary macroadenomas and Cushing's syndrome

Abstract

Cushing's Syndrome (CS) is the second most common endocrine disorder observed in dogs. The main cause
is the development of a tumor in the corticotroph area of the pituitary gland (corticotropinoma), which
releases excessive amounts of ACTH. These tumors are classified based on their size as microadenomas
and macroadenomas. Macroadenomas can be either large simple adenomas or they can progress into the
so-called giant invasive tumors, which can be malignant. Boxers are one of the predisposed breeds to
develop CS and often present with pituitary macroadenomas, as reported by the Endocrinology Department
at the Veterinary School of the University of Buenos Aires. Magnetic resonance imaging has revealed
differences between the macroadenomas found in brindle boxers and fawn boxers. Brindle boxers tend to
have the giant invasive variant (worse prognosis), with a survival rate of up to 6 months, while fawn boxers
have an extended survival of up to 3 years.