Hyperparathyroidism Jaw Tumor Syndrome Presenting as Recurrent Femur Fractures in a Young Woman; a Rare Presentation of a Rare Disease

BACKGROUND: Primary hyperparathyroidism usually occurs secondary to parathyroid adenoma, multiglandular hyperplasia, or parathyroid carcinoma. The patients usually present with incidentally discovered high calcium level and systemic or skeletal manifestations. In young patients with primary hyperparathyroidism, familial syndromes including multiple endocrine neoplasia types 1, 2, and 4 and hyperparathyroidism jaw tumor syndrome should be considered. Case Description. We present a case of a 22-year-old Sri Lankan woman who presented with femur fractures in a background of childhood nephroblastoma and maxillary fibro-osseous tumor. The patient had biochemical parameters suggestive of primary hyperparathyroidism with a parathyroid mass. The histology following excision of the mass revealed a parathyroid adenoma. Based on the associated clinical manifestations, hyperparathyroidism jaw tumor syndrome was suspected, and genetic studies reported a positive CDC73 mutation with a whole-gene deletion of exon 1–17. CONCLUSION: Hyperparathyroidism jaw tumor syndrome is an important diagnosis to consider in a young patient presenting with classic clinical features due to the risk of malignancy, familial involvement, and need to monitor for progressive systemic manifestations. As this is a rare disease, it can often be missed due to low degree of suspicion and the ability of the jaw tumor to mimic a metastatic deposit.