Bohannon LK, Pollard RE, Feldman EC.
Introduction/Purpose: The purpose of this study was to determine the prevalence of subclinical thyroid nodules in dogs that undergo cervical ultrasound as a diagnostic procedure for the assessment of hypercalcemia. Our hypothesis is that incidental thyroid masses are present in dogs.Methods: All dogs that underwent a cervical ultrasound examination as a component of the diagnostic assessment for hypercalcemia at the University of California, Davis Veterinary Medical Teaching Hospital between January 2010 and December 2011 were considered for inclusion. Dogs with a palpable neck mass where a thyroid gland lesion might have been suspected were excluded. Medical records were reviewed for signalment; clinical features; and results of clinicopathologic testing; endocrine testing and diagnostic imaging. Retrospective evaluations of cervical ultrasound images were performed and the presence or absence and number of thyroid nodules were recorded. The length, width, and height of the thyroid nodule were determined. The results of nodule aspirate, biopsy or necropsy were recorded when available.Results: Fifty-four dogs met the inclusion criteria. Ultrasound found that 8/54 (15%) dogs had at least one thyroid mass. Of the 8 dogs with a thyroid mass 3 had a histological diagnosis. 1/8 (13%) had 2 thyroid masses 1 of which was a thyroid gland follicular adenoma (length 0.52 cm, width 0.55 cm, height 0.50 cm) and the other was a follicular cyst (length 1.1 cm, width 0.90 cm, height 0.91 cm), 1/8 (13%) had nodular hyperplasia (length 2.75 cm, width 1.25 cm, height 1.19 cm), and 1/8 (13%) had thyroid carcinoma (length 2.05 cm, width 2.16, and height 1.22 cm).Discussion/Conclusion: The results suggest subclinical thyroid masses are present in dogs who initially present for hypercalcemia without a palpable neck mass. The clinical significance and management of incidentally identified thyroid nodules found during cervical ultrasound deserves further investigation.