Parathyroid carcinoma presenting with type 1 renal tubular acidosis

Primary hyperparathyroidism usually caused by parathyroid adenoma, parathyroid hyperplasia or rarely parathyroid carcinoma (PTC). PTC accounts for 0.4% to 5.2% of all reported cases of hyperparathyroidism, which is approximately 0.2% to 0.5% of malignant endocrine tumors overall. Renal tubular acidosis has been reported to be associated with primary hyperparathyroidism. We report a case of parathyroid carcinoma diagnosed with only using the minor criteria who had concurrent renal tubular acidosis. This case highlights the importance of keeping the suspicion of PTC in mind when clinically hypercalcemic patients presented with abnormally high serum calcium levels.