Parathyroid carcinoma and hungry bone syndrome

We hereby report two patients with parathyroid carcinoma presenting extremely high calcium and PTH levels, severe bone disease, and palpable neck mass at diagnosis. They both underwent parathyroidectomy, and one of them evolved to lung metastasis. Important hypocalcemia was observed after surgery in both: after parathyroidectomy in one patient, and only after surgical removal of the metastasis in the other. Both required intravenous calcium replacement, thus revealing hungry bone syndrome (HBS). HBS usually reflects rapid mineralization after correction of hyperparathyroidism. The more severe the bone disease before surgery, the more prone the patient is to HBS after surgery. Despite being an unfavorable outcome, HBS state suggests that surgical removal of hypersecretory parathyroid tissue was accomplished. In this study, HBS was observed in both patients, who presented severe bone disease prior to surgery. HBS would be expected post-operatively in successful parathyroid carcinoma removal.