‣What is the pathophysiology of Brown's tumor?Low vitamin D activation due to renal damage ➔ low calcium in blood ➔ secondary hyperparathyroidism ➔ excessive osteoclastic resorption ➔ Osteotitis Fibrosa Cystica (brown tumor)Decreased renal excretion of phosphate ➔ high phosphate levels‣What do they present with?Cystic lesions - commonly occur in mandible, maxilla but can also occur in other parts of the body‣What investigations?PTH levels‣Management of brown's tumor?Treat underlying renal problem‣How to tell secondary vs tertiary parathyroidism?