Endocrine Abstracts

Patient DE, a 49-year-old woman, was operated in 2005 for two giant-cell tumours of the mandible, and in 2008 for another tumour with the same localisation and histology. Inferior cervical ultrasound after the second surgery revealed a parathyroid adenoma of 20×27×15 mm behind the lower pole of the right thyroid lobe, confirmed by Tc tetrofosmin scintigraphy. The patient had metabolic features suggestive for primary hyperparathyroidism: calcium – 10.9 mg/dl (normal range – 8.5–10.2), phosphate – 1.6 mg/dl, (2.4–4.1), calciuria – 376 mg/24 h, (50–250), in the presence of very high serum levels of parathyroid hormone – 1311 pg/ml, (10–69). DXA-evaluated BMD was in the osteoporotic range at the spine (T score of – 3.3), but not at the hip and radius level. The patient was submitted to parathyroid surgery. The lower right parathyroid gland contained a parathyroid adenoma with oxyphylic cells. The surgeon excised a second lesion at the opposite side, suspected to be a second parathyroid adenoma, but proving by histology to be a thyroid adenoma. PTH levels remained however increased one month after surgery (124.5 pg/ml) with abnormal metabolic profile, suggesting remnant hyperparathyroidism and implicitly the presence of at least one other parathyroid adenoma. A new surgical intervention was therefore scheduled. Jaw brown tumours with giant cells may represent the unique symptom of primary or secondary hyperparathyroidism, but may equally be a sign for the rare hyperparathyroidism–jaw tumour syndrome produced by autosomal dominant mutations of the HRPT2 gene (1q31.2), encoding parafibromine, a tumour suppressor with apoptotic effect. Although no familial aggregation was known, the presence of multiple adenomas and the histological aspect, with frequent nuclear inequalities, were suggestive for the hyperparathyroidism–jaw tumour syndrome, and investigation of the HRPT2 gene was therefore initiated. If mutation is found, genetic screening of all first degree relatives is of importance.