Ectopic Parathyroid Adenoma Presenting as a Mediastinal Mass.

A parathyroid adenoma present in an ectopic site, in the anterior mediastinum, is a rare cause of persistent hyperparathyroidism. Though its occurrence in the mediastinum is unusual, existence has been noted in literature for more than a century. We describe a case of a 35-year-old male presenting with complaints of pain abdomen, clinically diagnosed as acute necrotizing pancreatitis, with raised serum calcium. Patient received symptomatic treatment for the pancreatitis which subsided. However, high levels of serum calcium persisted. Suspecting hyperparathyroidism, ultrasound neck was done, revealing apical thoracic mass. CT scan of neck revealed a large heterogeneous enhancing mass in superior mediastinum. Fine Needle Aspiration (FNA) of the mass done endoscopically was confusing as it showed features suggestive of a cystic teratoma. However, persistently raised calcium levels along with raised parathormone warranted a Technetium - 99 (Tc-99m) sestamibi scan which revealed positive uptake involving right inferior parathyroid extending to superior mediastinum. The mass was surgically excised and it was diagnosed as a parathyroid adenoma. This case helps bring to light the necessity to consider ectopic parathyroid adenoma as an important differential diagnosis in mediastinal tumour with persistent hypercalcaemia, and as a cause of hyperparathyroidism.