Resolution of primary hyperparathyroidism following surgical removal of cervical thymus

Recent research has emphasized the capacity of thymus cells of producing parathyroid hormone (PTH) if adequately stimulated, and have investigated the role of the so-called “thymic PTH”, produced by the medullary thymic epithelial cells (m-TECs). To the best of our knowledge, only a single case of well-documented PTH secretion from a thymoma causing primary hyperparathyroidism (PHTP) has been reported in the literature so far. We report here the case of a female patient with PHTP who underwent neck exploration for a suspected parathyroid adenoma. After surgery, a normalization of serum PTH concentration was observed, but the histological examination of the surgically excised mass revealed exclusively normal thymus tissue. The present case provides additional evidence of PHTP caused by an ectopic thymus.