Amino-aciduria Secondary to a Functioning Parathyroid Carcinoma

Abstract

A 48-year-old Lebanese housewife presented the clinical, laboratory, and radiologic findings of hyperparathyroidism. Kidney function tests were normal, and there were no other associated diseases. Exploration of the neck revealed a 4 by 4 cm mass at the left lower pole of the thyroid. The tumor was excised and a total thyroidectomy performed. Microscopy of the gland revealed a parathyroid carcinoma with invasion of the capsule and extracapsular capillaries. The two superior parathyroids were found embedded in the thyroid gland. Postoperatively the patient developed hyperparathyroidism and had to be maintained on calcium and vitamin D. Determination of total a-amino acids on preoperative urine samples revealed a definite amino-aciduria. Two-dimensional paper chromatography showed the amino-aciduria to be generalized. Following surgery there was return of the urinary amino acids to normal levels. The occurrence of amino-aciduria in hyperparathyroidism, if established, would be another instance of association of deranged calcium and phosphorus metabolism and amino-aciduria, and would raise the problem of a possible role of the parathyroid hormone in renal amino acid transport. Acute experiments done by injecting parathormone Lilly m- to rats did not produce amino-aciduria.