NOTE Surgery Identification and preservation of the parathyroid gland during total thyroidectomy in dogs with bilateral thyroid carcinoma: a report of six cases

ABSTRACT. Simultaneous removal of bilateral thyroid tumors was performed while preserving the parathyroid gland in six dogs. At least one external parathyroid gland was identified in all dogs. In five cases, the external parathyroid gland and its blood supply were preserved intact. In one dog, the vessels supplying the external parathyroid gland had been invaded by the tumor, and the gland was thus removed and reimplanted into the sternohyoid muscle. That dog required postoperative treatment with oral calcium gluconate and vitamin D3. Local tumor recurrence was not observed in any of the cases. The mean survival time was 920 days. We found that the external parathyroid gland could be identified and preserved in most dogs undergoing total thyroidectomy. KEY WORDS: bilateral thyroid carcinoma, canine, hypocalcemia, parathyroid gland identification, parathyroid gland preservation doi: 10.1292/jvms.13-0488; J. Vet. Med. Sci. 77(6): 747–751, 2015 Thyroid tumors account for 1.2–3.8 % of all tumors in dogs [3, 7]. Carcinomas are more common than adenomas and represent 90 % of thyroid tumors. These tumors typically develop in older dogs; 90 % of affected dogs are older than 7 years of age [22]. Bilateral tumors were reported in as many as 60 % of the dogs in one study [20], but another reported bi-lateral tumors in only 20 % of dogs [10]. Thyroid carcinoma