Case Of the Month

Adrenal Mass

The patient is a 12-year-old spayed female Jack Russell Terrier. The abdomen was progressively swollen on presentation. Only minor anemia was present with otherwise normal blood work. Chest radiographs reveal normal heart size and normal lung fields. 1-2 liters of ascites had been drained from this patient weekly after abdominal tap revealed modified transudate fluid. Abdominal sonogram was performed to decipher the cause of ascites.

DX

Post-mortem histopathology confirmed left adrenal cortical adenocarcinoma.

Outcome

Outcome: The patient was euthanized after 18 months form the original diagnosis of left adrenal mass and CVC invasion. Palliative therapy and weekly drainage of abdominal fluid created owing to portal hypertension and vena caval obstruction by the mass.

Comments

Special thanks to Dr. Brian Barnes and his dedicated staff at Westview Veterinary Hospital in Powell River, B.C, Canada for their long- term dedication to this patient.

Clinical Differential Diagnosis

(Lobetti): 1. Liver disease – neoplasia, cirrhosis, chronic-active hepatitis

2. Intra-abdominal neoplasia

3. Vena cava obstruction – compression, invasion, thrombosis

Sampling

Sampling: US-guided Cytology revealed left adrenocortical carcinoma at initial diagnosis.

Sonographic Differential Diagnosis

Left adrenal mass with vena caval invasion to the level of the right atrium.
Passive congestion and secondary ascites.
Hepatic portal hypertension, hepatomegaly with no signs of metastasis.

Image Interpretation

(Lindquist): Image 1: Mildly echogenic ascites is noted around the urinary bladder. Image 2-3: Long axis view of a mass invading the caudal vena cava with color flow demonstrating an obstructive process. Images 4-6: Left adrenal mass invading the vena cava. Image 7: Passive congestion pattern is noted in the liver with dilated hepatic vein to the right of the diaphragm and dilated CVC cranial to the diaphragm. Image 8: Passive congestion of the hepatic veins is noted with heterogenous liver parenchyma and mildly echogenic but normal sized GB. Image 9: Severe dilation of the CVC is noted as it passes through the diaphragm. The arrows demonstrate the walls of the CVC that is expanded and invaded by the mass. Image 10: Severe abdominal distention and venous congestion prior to therapeutic abdominocentesis that was repeated as needed over 18 months. Images 11-12. Progressed adrenal mass expansion in the CVC as it passes through the diaphragm not allowing for hepatic vein drainage into the CVC. Hence ascites continues to form 6 months from the original diagnosis of invasive left adrenal tumor. Image 13: Right parasternal short axis heart based view demonstrates progressive adrenal mass/thrombus extension into the right atrium and into the tricuspid annulus by means of the thoracic vena cava. Images 14-15: Post mortem images of the invasive left adrenal adenocarcinoma 18 months after the original diagnosis was made.