Case Study

Right parathyroid adenoma and branchial cyst in a 15 year old FS Beagle dog

A 15-year-old FS Beagle, with current medications of Enalapril, Soloxine, and Lasix for history of managed cardiac disease was presented for restlessness and inability to get comfortable. Abnormalities on physical examination were painful cranial abdomen and pain on the lumbar spine. CBC was within normal limits. Abnormalities on blood chemistry were mildly elevated AST, moderately elevated ALT and ALP, elevated BUN, elevated BUN/Creatinine ratio, hypercalcemia (both total and ionized), and elevated PTH. Urine culture yielded no growth.

DX

Right parathyroid adenoma and a branchial cyst.

Sonographic Differential Diagnosis

Right parathyroid tumor and potential second right parathyroid tumor or cyst adjacent to the right thyroid lobe. Moderate degenerative thyroid changes.

Image Interpretation

The thyroid regions in this patient were imaged. The left thyroid lobe presented moderate, chronic parenchymal changes with undulation of the thyroid capsule and areas of echogenic remodeling. This is consistent with degenerative changes. The right thyroid lobe presented similar changes. However, a 0.83 x 0.62 cm hypoechoic nodule was noted at the cranial pole of the right thyroid. An adjacent hypoechoic structure, that measured 0.8 cm, was also noted outside the right thyroid impinging on the thyroid capsule. This could be consistent with a cyst or second parathyroid tumor. Resection of both structures would be recommended.

Outcome

Resection of the right parathyroid tumor and cyst/tumor as well as potential cystotomy was recommended for the patient. The patient underwent surgery with removal of the parathyroid gland and cystotomy without event. The calcium level dropped post-operatively, and the patient was started on Calcitriol and Tums. After several days at home with the owners having great difficulty administering medication, the patient was admitted for intravenous fluids and follow-up blood work. Abnormalities on blood chemistry were high ALP, mild azotemia, and hypercalcemia of 13.1 mg/dL. After 24 hours on fluids the patient’s calcium levels normalized and the mild azotemia had improved. The patient remained on fluids for a few more days with recheck blood work remaining mostly unchanged and calcium level still within normal limits. Follow-up blood work three days later found hypercalcemia of 13 mg/dL and mild azotemia. At last communication, the patient was not eating well, and the calcium level was 15.5 mg/dL with mild azotemia still present. A second parathyroid tumor may have been also present but not visible on ultrasound. The patient was then lost to follow-up.

Clinical Differential Diagnosis

Primary hyperparathyroidism – neoplasia. Uroliths. Spinal arthrosis. Abdominal pain – renolith, ureterolith, pancreatitis, hepatopathy, focal peritonitis.