Endocrine Abstracts

Introduction: Hyperparathyroidism is a common medical condition, but in 5-10% of cases, it is part of Jaw Tumor syndrome, an autosomal dominant syndrome linked to a mutation in the HRPT2 gene. This syndrome is characterized by the presence of mandibular brown tumors and primary hyperparathyroidism.

Case report: A 24-year-old patient with a history of severe chronic renal failure in the left single kidney, presenting ureterohydronephrosis, underwent mandibular surgery for a brown tumor exhibiting histological characteristics of bony giant cells. Clinically asthenia, nausea, abdominal pain, constipation, and bone pain, Tachycardia:110 beats/min and painless mass in the right mandible, Laboratory tests indicated primary hyperparathyroidism with corrected serum calcium: 94 mg/l, serum phosphorus of 12.41 mg/l, and PTH:790 pg/ml. Scintigraphic examination showed focal retention of MIBI-Tc99m in the left and right thyroid lobes, measuring 6.7 4.4 mm and 4.4 4.3 mm, respectively, suggestive of pathological parathyroid tissue. The patient underwent parathyroid tumor resection, and the histopathological study confirmed parathyroid adenoma without signs of malignancy; however, molecular genetic study could not be performed. The patient’s clinical and biological conditions improved significantly during the follow-up.

Discussion: Hyperparathyroidism-Jaw Tumor Syndrome is an inherited disorder associated with increased activity of the parathyroid glands. Due to its rare diagnosis, especially considering its familial nature and the elevated risk of parathyroid carcinoma. Genetic studies should focus on identifying mutations in the HRPT2 gene. Hyperparathyroidism in individuals with HPT-JT is commonly caused by a parathyroid adenoma, leading to symptoms such as kidney stones, reduced bone mass, fatigue, muscle weakness, and bone or joint pain. Surgical removal of a parathyroid gland with a tumor, along with jaw tumor removal, may be necessary for treatment.

Conclusion: The presence of recurrent or multiple jaw lesions or the combination of jaw lesions with hyperparathyroidism bone disease on imaging should prompt consideration of HPT-JT. Early detection and treatment of hyperparathyroidism in this context allow for the timely identification of malignant disease and screening of family members.

References: 1. Hobbs M, Pole A. Hyperparathyroidism-jaw tumour syndrome. 1999 ;64: 518–525. doi: 10.1086/302259.

2. Liu Y, Wang H, You M, Yang Z, Miao J, Shimizutani K, Kpseki T. Ossifying fibromas of the jaw bone: 20 cases. doi: 10.1259/dmfr/96330046.

3. https://doi.org/10.1016/j.ando.2021.08.572