Sphenoid brown tumor associated with a parathyroid carcinoma

Brown tumors are osteolytic bone lesions that occur as a result of persistent hyperparathyroidism. They usually appear late in the natural history of the disease and are currently very rare due to an earlier diagnosis of primary hyperparathyroidism. We present the case of a 53-year-old female with a 2-month history of bitemporal hemianopsia and diplopia. A computed tomography showed an osteolytic bone lesion that involved the sphenoid corpus and clivus. A biopsy was made and the histopathology result was consistent with a brown tumor. The aforementioned location is very infrequent to such tumors, and therefore represented a diagnostic challenge. However, in this case, its association to primary hyperparathyroidism was the clue for the diagnosis. The association of a brown tumor secondary to a parathyroid carcinoma has been seldom reported. This case represents, to our knowledge, one of the few brown tumors described in such location and the first secondary to a parathyroid carcinoma.