Primary hyperparathyroidism due to overactive intrathyroid parathyroid glands: a potential cause of failed exploration.

The variable location of the parathyroid glands is a significant factor in unsuccessful cervical exploration for hyperparathyroidism. Particular difficulty may be experienced when an overactive parathyroid is concealed within the substance of the thyroid. Currently available methods of localizing abnormal parathyroid tissue may well fail to indicate an intrathyroid location. The latter possibility should always be considered whenever thorough cervical exploration has failed to reveal a parathyroid tumour as such awareness may obviate re-exploration or an unnecessary sternotomy. This report details the clinical features and operative findings in 6 patients whose primary hyperparathyroidism was due to an overactive intrathyroid parathyroid gland. Successful parathyroid surgery demands a strict routine exploration of the possible sites of overactive glands, virtually all of which are easily accessible through a standard collar incision.