Skull Tumors

Tumors arising in the skull represent the entire panoply of neoplasms that arise in (or metastasize to) extracranial bone, along with some that are typically confined to the cranium (cranial vault and skull base). These include both tumors primary to the bone and those metastatic to it from systemic cancers. The benign primary tumors include: osteomas and their variant, the osteoblastoma; hemangiomas and lymphangiomas; epithelial inclusion cysts, which can be dermoid or epidermoid tumors; chondromas; giant cell tumors; and intraosseous meningiomas. Osteomas are the most common of the primary skull tumors. Because these tumors need treatment only if symptomatic, a summary of their radiographic features is included to enable their identification as benign and nonthreatening without the intrusion of a biopsy. The exception is the giant cell tumor, which can require multimodal therapy and for which targeted medical therapy is now available. Their more aggressive counterparts include: osteosarcomas, the most common malignant bone tumor; fibrosarcomas; and the chordomas and chondrosarcomas that favor the skull base location. Metastatic tumors arise most commonly in patients with carcinomas of lung, breast, or prostate, and in the majority of cases are treated with either systemic chemotherapy or local irradiation; surgery is usually reserved for those that pose neurological risk from inward growth and dural invasion. Lymphoma, Ewing sarcoma, plasmacytoma/myeloma, and neuroblastoma can each spread into the skull, but they are uncommon in this location and require coordinated oncologic care. A group of reactive proliferative lesions that cause focal thickening of the skull, but are not neoplasms, includes focal thickening from Paget disease, fibrous dysplasia, and Langerhans cell histiocytosis. The identification, biologic behavior, and current modes of therapy are described for each.