Brown tumors: an uncommon manifestation of bone disease in primary hyperparathyroidism

Bone involvement in primary hyperparathyroidism (PHPT) is characterized by decreased bone mineral density, bone resorption at both trabecular and cortical sites and bone erosions, up to brown tumors (BT) and cysts, the so-called osteitis fibrosa cystica (OFC). Signs and symptoms of OFC include bone pain, muscle weakness, skeletal deformities and pathological fractures. In recent years, PHPT has greatly changed its clinical expression, especially in Western countries. For these reason BT, a typical expression of OFC, are always less observed and often mistaken for malignancy. An integrated diagnostic approach, considering first a complete biochemical panel and a confirmation by functional imaging, is crucial for a correct diagnosis, mostly considering that such skeletal manifestations may be reversible after surgical cure of PHPT.