Endocrine Abstracts

Hyperparathyroidism-jaw tumour syndrome (HPT-JT) is a rare autosomal dominant condition characterized by primary hyperparathyroidism (<90%) as a result of parathyroid adenoma or carcinoma (10–15%), ossifying fibromas of mandible and maxilla (30–40%), renal lesions (20%) most commonly cysts and benign and malignant uterine tumours and caused by germline CDC73 pathogenic gene mutations. Currently only 200 cases reported in medical literature. His management has proved more difficult which may be associated with this novel CDC73 pathogenic gene mutation. A 31-year-old man presented with polydipsia, fatigue, corrected calcium of 4.3 and PTH 147. USS and CT neck revealed a left inferior parathyroid adenoma, confirmed by exploration. Histology showed disruption of the capsule with fibrous tissue extending into the lesion at one pole although no overt malignancy. A few months later he had recurrence of symptoms, further hypercalcaemia and a right inferior parathyroid adenoma was excised. Genetic testing detected a novel pathogenic duplication mutation of CDC73 gene leading to premature termination of translation. He presented a third time with hypercalcaemia. No adenoma was identified on imaging however he declined selective venous PTH sampling. His case was extensively discussed with multiple specialists with differing opinions as to total parathyroidectomy +/− auto transplantation. Patient elected for total parathyroidectomy and no auto transplantation due to his germline CDC73 pathogenic gene mutation and 10–15% risk of parathyroid carcinoma development. This unique case illustrates consideration of genetic testing in primary hyperparathyroidism under 45 years, with challenges in rarity and management including implications for biopsy and surgical intervention, multisystem lifelong screening of proband and relatives which is recommended from 5 to 10 years and availability of predictive genetic testing for the familial CDC73 gene mutation. This indicates a significantly more complex case where previous literature has been unable to guide on management and may help advise other endocrinologists.