Brown tumor mimicking maxillary sinus mucocele as the first manifestation of primary hyperparathyroidism.

We describe the first case of brown tumor mimicking a maxillary sinus mucocele as the first manifestation of the patient's primary hyperparathyroidism. A 34-year old woman presented with a 14 days history of elevation of the right orbit, retrobulbar pain and cheek anesthesia. The CT and MR evaluation showed a mass, initially described as mucocele of the right maxillary sinus. The laboratory studies revealed hyperparathyroidism. The patient underwent acute surgery, and the mass appeared clinically as mucocele. The histological examination of the resected lesion revealed changes representing either giant cell granuloma or brown tumor. The finding of hyperparathyroidism confirmed the diagnosis of brown tumor. To our knowledge, this is the first report of cystic brown tumor mimicking a mucocele of the maxillary sinus.