Primary hyperparathyroidism is most commonly caused by a single adenoma (80-90%). Laboratory investigations are likely to show elevated serum intact parathyroid hormone (PTH), alkaline phosphatase (ALP) and ionized serum calcium, and low serum phosphate. Besides the signs and symptoms of hypercalcemia, patients present with calcification of menisci and articular cartilage, erosions in hand bones, “salt and pepper skull”, and brown tumors (osteoclastomas), which appear as lytic regions expanding the cortex and causing pathological fractures, so named because of hemosiderin deposition.
AP radiograph showing a lytic expansile lesion with pathological fracture in metadiaphyseal region of left humerus with similar lesion in the fifth posterior rib.
AP radiograph showing a lytic expansile lesion in the third metacarpal of the right hand and the fifth metacarpal of the left hand.