Incidence, survival time, and surgical treatment of parathyroid carcinomas in dogs: 100 cases (2010-2019).

OBJECTIVE: To evaluate outcomes of dogs with parathyroid carcinoma (PTC) treated by surgical excision and to describe the incidence of postoperative hypocalcemia, degree of hypocalcemia, duration of hospitalization, duration of calcium supplementation, and survival time. ANIMALS: 100 client-owned dogs with PTC admitted to academic, referral veterinary institutions. PROCEDURES: In a retrospective multi-institutional study, medical records of dogs undergoing surgical excision of PTC between 2010 to 2019 were reviewed. Signalment, relevant medical history, clinical signs, clinicopathologic testing, imaging, surgical findings, intraoperative complications, histologic examination, and survival time were recorded. RESULTS: 100 dogs with PTC were included, and 96 dogs had clinical or incidental hypercalcemia. Common clinical signs included polyuria (44%), polydipsia (43%), hind limb paresis (22%), lethargy (21%), and hyporexia (20%). Cervical ultrasonography detected a parathyroid nodule in 91 of 91 dogs, with a single nodule in 70.3% (64/91), 2 nodules in 25.3% (23/91), and ≥ 3 nodules in 4 (4/91)% of dogs. Hypercalcemia resolved in 89 of 96 dogs within 7 days after surgery. Thirty-four percent of dogs developed hypocalcemia, on the basis of individual analyzer ranges, within 1 week after surgery. One dog had metastatic PTC to the prescapular lymph node, and 3 dogs were euthanized for refractory postoperative hypocalcemia. Estimated 1-, 2-, and 3-year survival rates were 84%, 65%, and 51% respectively, with a median survival time of 2 years. CONCLUSIONS AND CLINICAL RELEVANCE: Excision of PTC results in resolution of hypercalcemia and excellent long-term tumor control. Surgical excision of PTC is recommended because of resolution of hypercalcemia and a good long-term prognosis. Future prospective studies and long-term follow-up are needed to further assess primary tumor recurrence, metastasis, and incidence of postoperative hypocalcemia.

Outcomes for dogs with primary hyperparathyroidism following treatment with percutaneous ultrasound-guided ethanol ablation of presumed functional parathyroid nodules: 27 cases (2008-2011).

OBJECTIVE: To describe outcomes for dogs with primary hyperparathyroidism following treatment with percutaneous ultrasound-guided ethanol ablation of presumed functional parathyroid nodules. DESIGN: Retrospective case series. ANIMALS: 24 dogs with primary hyperparathyroidism that underwent 27 ultrasound-guided ethanol ablation procedures of presumed functional parathyroid nodules identified by cervical ultrasonography. PROCEDURES: Dogs were anesthetized for each procedure. For each nodule, 95% ethanol was injected into the center with ultrasound guidance (volume injected calculated on the basis of ultrasonographic measurements). The interval from treatment to resolution of hypercalcemia, complications, and follow-up clinicopathologic data were recorded. RESULTS: 5 procedures involved simultaneous treatment of 2 nodules. Three dogs underwent a second treatment because of initial treatment failure or development of another nodule. Hypercalcemia resolved after 23 of 27 (85%) procedures. In those 23 treatments, 22 (96%) had resolution of hypercalcemia within 72 hours after treatment. Hypocalcemia was detected in 6 different dogs at 2 (1 dog), 7 (3 dogs), 14 (1 dog), and 21 (1 dog) days after treatment; 5 of these dogs had mild transient hypocalcemia and 1 developed clinical signs requiring calcium supplementation. Although there were no periprocedural adverse effects, 2 dogs had delayed adverse effects; the overall rate of complications (including delayed adverse events and clinical hypocalcemia) was 11.1%. Long-term follow-up data indicated sustained normocalcemia in 17 of 19 dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that percutaneous ultrasound-guided ethanol ablation of functional parathyroid nodules may be an effective treatment for primary hyperparathyroidism of dogs, with short duration of anesthesia, minimal complications, and low risk for hypocalcemia.

Percutaneous ultrasound-guided chemical parathyroid ablation for treatment of primary hyperparathyroidism in dogs.

OBJECTIVE: To evaluate the efficacy, feasibility, and safety of ultrasound-guided chemical ablation of parathyroid masses in dogs with primary hyperparathyroidism. DESIGN: Prospective clinical trial. ANIMALS: 8 dogs. PROCEDURE: In all dogs, a solitary parathyroid mass was evident ultrasonographically. Dogs were anesthetized with propofol, and a 27-gauge needle was directed into the parathyroid mass under ultrasound guidance. Ethanol (96%) was injected into the mass until there was evidence of diffusion of fluid throughout the mass. Serum total calcium, ionized calcium, phosphorus, and parathyroid hormone (PTH) concentrations were monitored daily for 5 to 7 days after the ablation procedure and again 1, 3, and 6 months after the procedure. Dogs were also monitored for adverse effects. Follow-up ultrasonography was performed 5 days and 1 month after the ablation procedure. RESULTS: One injection was required in 7 dogs, and 2 injections were required in 1. Serum total and ionized calcium concentrations were within reference ranges within 24 hours after treatment in 7 dogs and within 5 days in 1 dog. Serum PTH concentration decreased and serum phosphorus concentration increased within 24 hours after treatment in all 8 dogs. Transient hypocalcemia developed in 4 dogs during the first 5 days after treatment, but only 1 dog required treatment for hypocalcemic tetany. Hypercalcemia recurred in 1 dog 1 month after the procedure and surgical removal of the parathyroid mass was required. Other adverse effects were not reported. CONCLUSIONS AND CLINICAL RELEVANCE: Ultrasound-guided chemical ablation of parathyroid masses is a safe and effective alternative to surgery for dogs with primary hyperparathyroidism.

Primary hyperparathyroidism in dogs: 21 cases (1976-1986).

Case records from 21 dogs with hypercalcemia and hyperparathyroidism were evaluated. The dogs were greater than or equal to 7 years old, and 6 were Keeshonds. The most common clinical signs were polydipsia/polyuria, listlessness, and muscle weakness. The serum calcium concentrations were 12.1 to 19.6 mg/dl. Serum phosphorus concentrations were low in 5 dogs, within the reference range in 13 dogs, and high in 3 dogs that also had high concentrations of BUN. Twenty dogs had a parathyroid adenoma, and 1 had a parathyroid carcinoma. Nineteen dogs had their parathyroid tumor surgically removed. Within 5 days of tumor removal, 11 of the 19 dogs became hypocalcemic and the remaining 8, normocalcemic. Nine of the 11 hypocalcemic dogs developed clinical signs. Iatrogenic hypercalcemia was induced in 7 of 16 dogs treated orally with calcium carbonate plus vitamin D. Only 1 of 19 dogs that had their parathyroid tumor excised died in hypocalcemic tetany. Two additional dogs died within 2 weeks of surgery, one because of pancreatitis, the other due to renal failure. Eight dogs died 9 to 37 months after surgery of unrelated problems. Eight dogs were alive for at least 7 to 28 months after surgery.

Primary hyperparathyroidism in a dog.

A 6-year-old male Standard Poodle had hypercalcemia, hypophosphatemia, and a urinary concentrating defect. A parathyroid adenoma involving the left caudal parathyroid gland was surgically removed. Transient hypocalcemia followed, which resolved without treatment. A renal biopsy did not demonstrate renal parenchymal mineral deposition. Urinary concentrating ability returned after surgery.