Abstract
A review of the literature of osteoma of the cranial bones, especially that of osteoma of the frontal sinus, leaves one with a somewhat confused idea as to what osteoma really is. This is due to the following reasons: First, this lesion is relatively uncommon; second, its cause is not known, and, finally, the gross morphologic and microscopic studies have presented pictures that reveal wide variation. For instance, osteoma is portrayed by some observers as an ivory-like tumor mass of eburnated dense bone, while others present a picture of a tumor mass having a cancellous bony structure. Ewing stated that the bony structure may be ivory-like with solid lamellas and with few or no haversian canals, or it may be spongy with cancellous tissue and may contain marrow cavities or spaces. Schwartz1 defined osteoma as a bony tumor which exhibits neoplastic characteristics. For the main, one can be reasonably reconciled