Brown tumor of secondary hyperparathyroidism involving the superior orbit and frontal calvarium.

A 29-year-old white man with chronic renal failure on hemodialysis presented with a subacute onset of painful proptosis, inferior displacement and limited upgaze of his right globe, and a tender, palpable fronto-temporal mass beneath the right scalp. A cranio-orbitotomy was performed to completely excise a large, necrotic, multilocular, cystic, heterogeneous mass. Histopathologic examination with light microscopy demonstrated the characteristic findings of a giant cell tumor. Based on the patient's history of renal failure and laboratory evidence of hyperparathyroidism, a diagnosis of brown tumor was determined.