History is suggestive of blood filled bone tumor seen in Hyperparathyroidism. HYPERPARATHYROIDISM May be primary (due to adenoma or hyperplasia), secondary (due to persistent hypocalcemia) or tertiary (when secondary hyperplasia leads to autonomous overactivity). Fig. X-ray hand--hyperparathyroidism Fig. Brown tumor Figs. A and B: (A) Lamina dura and (B) Resorption of lamina dura Salt pepper skull Parathyroid adenoma Most common cause of primary hyperparathyroidism. Presents with subperiosteal resorption, and replacement of endosteal cavitation marrow by vascular granulation and fibrous tissue (osteitis fibrosa cystica). Classical and pathognomic feature of hyperparathyroidism is subperiosteal coical resorption of middle phalanges on radial aspect Clinical features- Abdominal groans (dyspepsia), psychic moans, renal stones and weak bones (Groans, moans, stones and Bones). Ix- Parathyroid hormone and S. alkaline phosphate are raised. Calcium is high, serum phosphate is low.