History Osteomata of the paranasal sinuses are relatively rare tumors, slow growing, and they usually do not produce any symptoms until the tumor has become moderate in size. They occur mostly in the frontal sinus, infrequently in the ethmoid and maxillary sinuses, and very rarely in the sphenoid sinus. The Danish anatomist, Bartholin, 5 who probably saw the first case of bony tumor in the skull about 300 yrs. ago, believed that he was dealing with "petrified brain." Vallisnieri, in 1733, was the first one to demonstrate that these lesions were not petrified, but simply bone tumors. The first case of surgical intervention in this country was by Knapp in 1880. Location Carmody, 2 in 1935, tabulated 139 of the recorded cases of osteomata of the accessory sinuses in the literature. There were 90 cases in the frontal sinuses, 9 in the ethmoids, 8 in the ethmoid and frontal, 6