Dog: Abdomen. Retroperitoneal hemorrhage secondary to malignant pheochromocytoma .

Dog: Caudal vena cava. Caudal vena cava with neoplastic thrombus caused by malignant pheochromocytoma.

Dog: Right adrenal gland. Malignant pheochromocytoma leading to fatal retroperitoneal hemorrhage.

Dog: Thyroid gland. Adrenal mass & thrombus .