Successful removal of a functional parathyroid adenoma using a radio-guided parathyroidectomy technique with a hand-held gamma detector and technetium Tc 99m sestamibi scintigraphy in a horse

This clinical case report details the use of a radio-guided parathyroidectomy technique using a hand-held gamma detector and technetium Tc 99m sestamibi scintigraphy for detection and removal of a functional parathyroid adenoma in a horse. An 18-year-old Arabian gelding was diagnosed with primary hyperparathyroidism based on persistent hypercalcaemia and increased parathyroid hormone concentration. Single gland disease was suspected after technetium Tc 99m sestamibi scintigraphy showed focal increased radiopharmaceutical uptake (IRU) at the thoracic inlet. Ultrasonography failed to identify a discrete mass in the region of IRU. Surgical excision was recommended; however, due to unreliable preoperative localisation, a radio-guided parathyroidectomy technique was elected. A radio-guided parathyroidectomy technique was performed under general anaesthesia using a hand-held gamma detector and technetium Tc 99m sestamibi scintigraphy to identify the parathyroid adenoma, which was subsequently excised. The horse recovered from the procedure without complication. Successful removal of the parathyroid adenoma was confirmed based on histopathological and serum bioch findings. Following the procedure, the horse showed no evidence of hyperparathyroidism and returned to light pleasure riding. Three years postoperatively, the gelding died of unrelated natural causes; a post-mortem examination was not performed. This radio-guided parathyroidectomy technique was effective in facilitating the removal of a parathyroid adenoma in this gelding and might be useful in other equids that have primary hyperparathyroidism IRU on technetium Tc 99m sestamibi scintigraphy, particularly if a discrete mass cannot be identified ultrasonographically.