Abstract. Abdominal ultrasound examination in an 11-year-old, intact, female Labrador dog with hepatic
disease revealed a nodular swelling of the left adrenal gland. Hyperadrenocorticism was suspected, but endocrine
tests were negative. At the owner’s request, an adrenalectomy was performed. Grossly, a nodular mass protruded
from the external surface of the left adrenal gland and in cut section was hemorrhagic and effaced the cortical
and medullary regions. Histologic examination revealed a cortical neoplasm with medullary involvement. The
mass was composed of well-differentiated adipose cells, megakaryocytes, hematopoietic cells, and macrophages