Atypical parathyroid adenoma: Severe manifestations in an adolescent girl

INTRODUCTION: Primary hyperparathyroidism (PHPT) is a disease that is usually diagnosed in an asymptomatic state during routine biochemical screening. It generally manifests as a sporadic disease in post-menopausal women. However, in India and developing countries, we continue to see severe skeletal and renal manifestations of the disease. CASE REPORT: Herein, we describe the case of a 16-year-old adolescent girl who presented with severe manifestations of primary hyperparathyroidism. Biochemically, she had severe parathyroid hormone (PTH)-dependent hypercalcaemia with hypophosphataemia and vitamin D deficiency (serum total Ca – 18.5 mg/dl [8.5–10.5 mg/dl], serum PO4 – 1.9 mg/dl [2.5–4.5 mg/dl], serum ALP – 2015 IU/l [80–240 IU/l], serum 25[OH]D – 19.1 ng/ml [30–100 ng/ml] and serum iPTH > 5000 pg/ml [15–65 pg/ml]). Pre-operatively, she required management with saline diuresis, bisphosphonate, and calcitonin. After surgery, the patient had severe hungry bone syndrome (serum Ca – 4.1 mg/dl, serum PO4 – 2.1 mg/dl, serum ALP > 10,000 IU/l) that required treatment with calcium infusions for almost 3 months. Although the clinical and biochemical picture was suggestive of parathyroid carcinoma, histopathology revealed atypical parathyroid adenoma with low proliferative index. Atypical parathyroid adenoma is a term applied to a neoplasm with ‘worrisome’ features but not fulfilling the ‘absolute histopathological criteria of malignancy’. CONCLUSIONS: Atypical parathyroid adenoma, a rare cause of PHPT, may be associated with severe manifestations. Although malignancy was not discerned in the immediate post-operative period, we plan to continue long-term follow-up of the patient to look for any signs of recurrence or development of parathyroid carcinoma.