Coincidence of hot thyroid nodules and primary hyperparathyroidism

Hyperthyroidism is frequently associated with hypercalcemia, which usually subsides after successful treatment of hyperthyroidism. Moreover, thyroid nodules are frequently detected by preoperative thyroid ultrasound in patients with primary hyperparathyroidism. Sensitised by the observation of a patient with coexisting hyperthyroidism and hyperparathyroidism we prospectively evaluated thyroid nodules in euthyroid patients with hyperparathyroidism by thyroid scintigraphy. Whereas the first patient with hyperparathyroidism was hyperthyroid the subsequent four patients with hyperparathyroidism and thyroid nodules had normal fT3 and fT4. Two patients had hypercalcemia and nephroureterolithiasis. Three patients suffered from hypercalcemia and bone pain due to osteoporosis. In the hyperthyroid patient hypercalcemia persisted after euthyroidism was achieved intact parathyroid hormone was found to be elevated. Subsequently, thyroid nodules, detected by preoperative ultrasound in four euthyroid patients with primary hyperparathyroidism, were identified as compensated hot nodules by thyroid scintigraphy. All patients underwent combined subtotal thyroidectomy and parathyroid resection. Histology showed hyperplastic parathyroid glands in one patient and a single parathyroid adenoma in four cases. Postoperatively calcium and PTH levels returned to normal and TSH levels increased in all patients. Persistence of hypercalcemia after successful treatment of hyperthyroidism should be reason for the determination of parathyroid hormone. Thyroid nodules detected by preoperative ultrasound in patients with hyperparathyroidism living in areas of iodine deficiency should be further evaluated by scintigraphy even if TSH is normal. In the case of hot thyroid nodules both parathyroid and partial thyroid resection should be performed.