Tumors of the skull.

Skull tumors comprise a wide variety of entities, ranging from chronic inflammatory diseases to primary and secondary neoplasms. There are no valid data about the incidence of skull tumors in general, but the epidemiology of single entities has been assessed. Osteoma is the most common diagnosis in benign skull neoplasms [21] and may be accompanied by Gardner's syndrome [2]. In most series, the second most common finding in benign calvarian tumors is hemangioma [8]. Benign osteoblastoma represents about 1% of all bone tumors, and a craniofacial localization is found in 15% of all osteoblastomas [2]. The most common malignant skull tumors are osteogenic sarcoma and chondrosarcoma. The former—in general– is the second most common primary malignant bone tumor after plasmocytoma. Osteogenic sarcoma occurs in all ages with a peak within the first 2 decades; 85% of osteogenic sarcoma arises before the age of 30 [23]. The main cranial locations are the maxilla and mandible, while manifestation in the calvaria is less common. In contrast, cranial chondrosarcoma arises preferentially at the skull base, accounting for 6% of all skull base tumors [9]. The highest incidence is found in the second decade; however, chondrosarcomas may be found at any age.