Case Study

Adrenal mass with caval invasion in a 13 year old FS DSH cat

A 13-year-old FS DSH cat was presented for the evaluation of polyuria and polydipsia of several months’ duration. The serum biochemical profile revealed marked hyperglycemia. The CBC showed a low RBC count, lymphopenia, and a monocytosis. The TT4 and free T4 were within normal limits. A fructosamine level was high. The urinalysis showed glucosuria, and hematuria. The urine culture was negative for bacterial growth. A fructosamine level was repeated a few months later and remained elevated. Insulin-like Growth Factor 1 was normal, and a diagnosis of acromegaly was considered unlikely. A recheck of the blood work revealed hyperglycemia, hyperphosphatemia, hypokalemia and hyperlipasemia. The CBC showed elevations of the MCH and MCHC, as well as thrombocytopenia. The results of an ACTH stimulation were suggestive of hyperadrenocorticism. The urine had a turbid appearance on the urinalysis and showed proteinuria, hematuria, and elevated RBCs microscopically. The urine culture was negative. Vitamin B12, folate concentrations were performed and the the folate was found to be elevated. High fTLI and a high PLI were also present. Fructosamine levels were now within normal limits.

Sonographic Differential Diagnosis

May 19: Left adrenal mass with caval invasion.
August 14: Progressive left adrenal mass with caval invasion approaching diaphragmatic inlet.

Image Interpretation

May 19: There is a left adrenal mass in this patient that has grown into the cava. The echogenic change in the caudal vena cava is occupying approximately 80% of the caudal vena cava and occupies a length of 4.1cm. However, this may not be clinically significant at this point.

August 14: The adrenal gland in this patient has grown from size from 2 – 2.5cm. Caval invasion through phrenic vein has occurred at increased distance of 7cm and approximately 1.5cm from the diaphragmatic inlet in the vena cava.

DX

Left adrenal mass with caval invasion

Outcome

The patient was referred for an abdominal CT scan. A heterogeneous, hypodense soft tissue mass obliterated the normal architecture of the left adrenal gland. There was also invasion of the caudal vena cava at the junction of the left renal vein and the middle of the mass. The right adrenal gland was not visualized. A focal, hypodense nodule was present in the caudate liver lobe. The cat was suspected to have a neoplasm affecting the left adrenal gland with metastases to the caudal vena cava, as well as possible left renal vein involvement. Presence of metastases to the liver could not be ruled out as not all of the liver was included in the study. Medical management was determined to be the best option in this case, as the patient was not considered a good candidate for surgery.

Clinical Differential Diagnosis

Diabetes mellitus in conjunction with pancreatitis, hypoaldosteronism secondary to an adrenal mass, such as an adenocarcinoma or adenoma.

Sampling

None taken

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