Endocrine Abstracts

Parathyromatosis is a persistent or recurrent hyperparathyroidism following parathyroidectomy. It usually presents as multiple nodules in the neck. Infrequently may present as a single palpable neck mass. It could be due to low grade malignancy, seeding of parathyroid tissue during parathyroidectomy and growth of persistent embryonic foci of parathyroid tissue. A 24-year-old patient presented with features of hypercalcaemia. She has undergone left inferior parathyroidectomy 1 year back which suggested a benign tumour. However, she has had persistent hyperparathyroidism and high calcium levels even after surgery. She also had multiple fractures in lumbar spine and right hip. She had been treated with IV hydration and zoledronic acid, cinacalcet, and calcitonine with no response. Her serum calcium level was 3.5 mmol/l inorganic phosphorus 1.68 mg/dl (2.5 – 4.5), intact PTH was 1900 pg/ml (10 – 65), her total bone density T score was -3.5. Her contrast enhances computer tomography neck revealed a mass of 4.2 × 2.7 × 3.7 cm inferior to the left lobe of the thyroid. Tc99m Sestamibi scan suggested of a residual parathyroid tissue. Genetic condition causing hyperparathyroidism were excluded. She had pepper pot skull and multiple brown’s tumours in the skull bones. The patient underwent excision of the parathyroid tumour with hemithyroidectomy. Her histology revealed extensive fibrotic and necrotic parathyroid tissue. Capsular and vascular invasion was not identified. Mitotic activities were increased. However, immunohistochemistry revealed Ki67 of 20% and positivity for chromogranin A and cyclinD1 weak to moderate positivity seen in 70 to 80 % and strongly positive in few cells. Post operatively her calcium and parathyroid hormone levels returned to normal. There is a spectrum of malignant parathyroid neoplasms according to the degree of invasiveness. It starts from parathyromatosis, atypical parathyroid adenoma and parathyroid carcinoma. This case therefore highlights a common presentation leading to rare diagnosis.