Parathyroid adenoma found by vertebral vein sampling

We report on a 33-year-old man with hypercalcemia and recurrent nephrolithiasis, who underwent the first neck exploration for primary hyperparathyroidism on September 27, 1973. No tumor was found and bilateral upper normal parathyroid glands were removed. However, hypercalcemia persisted postoperatively. Selective venous sampling for radioimmunoassay of parathyroid hormone 5 years later revealed a sharp unilateral gradient in the right vertebral vein. On November 2, 1978 the second neck exploration was performed and a right lower parathyroid adenoma was removed from the right lateral wall of the esophagus. Postoperatively, the serum calcium level decreased to 8.8 to 9.3 mg./dl. and convalescence was uneventful. In this case the pathway of parathyroid venous effluent might have been changed by the previous neck exploration and probably drained anomalously through the vertrbral vein. Selective venous sampling for radioimmunoassay of parathyroid hormone should include samplings from the vertebral veins as well as the thyroid veins, especially in cases with 1 or more previous neck explorations.