Case Study

Invasive right adrenal mass in a 10 year old MN Labrador Retriever

A 10-year-old MN Labrador Retriever dog was presented for the evaluation of polyuria and polydipsia of one week’s duration. Physical exam found the patient to be panting excessively, as well as having a pendulous abdomen. Blood chemistry revealed hyperbilirubinemia, an elevated GGT enzyme activity, hypercholesterolemia, hypertriglyceridemia, hypocalcemia, hypernatremia, hyperchloremia, a high BUN/Creatinine ratio, and a high calculated osmolality. The T4 was within normal limits. Urinalysis showed a high pH, low specific gravity, proteinuria, and the presence of bacteria.

Sonographic Differential Diagnosis

Invasive mineralizing right adrenal mass, non resectable. This is likely adenocarcinoma due to the invasive appearance and mineralization . Pheochromocytoma is less likely (few pheochromocytomas mineralize). Multiple “target” liver lesions strongly suggestive for metastatic disease.

Image Interpretation

The area of the right adrenal gland and vena cava (CVC) notes an aggressive mineralizing mass deriving from the right adrenal gland and invading the CVC in the region of the phrenic vein. No adrenal architecture is noted. The vena cava is expanded by the occupied mass. Attached thrombus likely also is responsible for part in the intra caval mass accumulation.The liver image revealed multifocal mixed hyper and hypoechoic nodular changes with disruption of hepatic infrastructure and “target” type appearance strongly suggestive for metastatic disease. Color flow Doppler evidences the persistence of venous flow around the mass.

DX

Invasive adrenal mass

Outcome

A recheck exam was performed one month later and he was found to have pale pink mucous membranes, a pendulous abdomen with a positive fluid wave on ballottment. Repeat blood chemistry revealed hypoproteinemia, hypoalbuminemia, elevations of the ALT, AST and GGT enzyme activities, hypocalcemia, hypernatremia, hyperphosphatemia and hypomagnesemia. The CBC showed the presence of decreased numbers of RBCs and a decreased hematocrit, and a leukocytosis consisting of a neutrophilia and monocytosis. The urinalysis showed a high pH, low specific gravity, and trace hematuria. The patient was then lost to follow-up.

Clinical Differential Diagnosis

Hepatic insufficiency (cirrhosis due to chronic active hepatitis, Labrador hepatopathy) with secondary cholestasis or cholangitis, pyelonephritis, neoplasia affecting the liver, biliary system, spleen (with metastases to the liver) or possibly the kidneys. Hyperadrenocorticism (pituitary-dependent or adrenal-dependent tumor (adenoma or adenocarcinoma), or an adrenal tumor causing the overproduction of sex hormones (atypical Cushing’s disease). This ddx becomes less likely when he is presented 2 weeks later for signs of anorexia, vomiting and polydipsia; at this point, neoplasia becomes much more likely.