Endocrine Abstracts

Case history: An 18 year old male student presented to the dentist with an eight week history of left-sided facial pain and swelling. He was subsequently referred to the maxillofacial team. His only previous medical encounter was for a traumatic right humerus fracture following a roller-skating injury. He took no regular medication. His father died of an unknown malignant process several years previous and family history was otherwise unremarkable. On questioning, the patient described symptoms of thirst, polyuria, lethargy, constipation and frequent headaches. Examination of the hard palate revealed a left-sided, firm 3x3 cm ulcerated mass with palatal expansion. Soft tissues were normal.

Investigations: Blood tests showed an elevated adjusted calcium 3.30 mmol/l (2.20-2.60), a low phosphate 0.50 mmol/l (0.80-1.50), and an elevated alkaline phosphatase of 799U/l (30-130). Renal and liver function were normal. Parathyroid hormone was markedly elevated at 126.56pmol/l (1.48-7.63), with a slightly low 25-hydroxyvitamin D3 30.1 nmol/l. Twenty-four hour urine collection (volume 5.3L) showed an elevated urinary calcium of 17.89 mmol/24h (2.50-7.50). Cross-sectional imaging (CT) of the facial bones revealed an expansile lytic lesion in the left maxilla with generalised osteosclerosis and multiple further small lytic lesions in the imaged bones. A 34mm nodule posterior to the right lobe of the thyroid was noted. Histology obtained from a biopsy of the palatal mass revealed features of a benign giant cell lesion with the histological differential diagnosis being between a giant cell granuloma and a hyperparathyroidism-related brown tumour.

Results and treatment: Blood tests and histology are in keeping with a diagnosis of primary hyperparathyroidism and in light of symptoms and significant hypercalcemia, Cinalcalcet was started along with vitamin D supplementation. Radiological appearances suggest multiple brown tumours with a nodule in keeping with a parathyroid adenoma. Histology supports the biochemical and radiological findings. Given his age, consent was obtained for genetic testing for Familial Primary Hyperparathyroidism. An important differential diagnosis to be considered is parathyroid carcinoma given the parathyroid hormone level.

Conclusions and points for discussion: This young male has severe symptomatic primary hyperparathyroidism with significant bone involvement. Brown tumours are now a rare presentation of hyperparathyroidism, in part due to increased frequency of blood tests undertaken in the general population and earlier diagnosis of primary hyperparathyroidism. It is important to screen all young people presenting with primary hyperparathyroidism for genetic causes which has potential implications for further screening of both the individual and family members. Genetic testing can also inform the surgical approach.