Background
Depending on the primary proliferating cell, both malignant and benign skull tumors can be any of the following:
Pathophysiology
Salivary gland tumors, as well as other malignancies of the head and neck, such as squamous cell carcinoma and esthesioneuroblastoma, may invade the skull base by proximity or by perineural invasion. [3, 2, 4] These tumors cause cranial nerve paralysis by invasion or direct extension; accompanying pain is due to erosion of the involved structures. Involvement of the periosteum or dura is the primary mechanism of direct tumor spread and the causative pathology.
Epidemiology
Frequency
United States
One of the most comprehensive reported series of bone tumors came from the Mayo Clinic. Of the 7975 bone tumors in the series, 4% involved the skull (excluding the mandible, maxilla, and nasal cavity), 19% were benign, and 81% malignant. As the Mayo Clinic is a tertiary referral center, some degree of selection bias probably was in effect.
-
Other studies estimate that skull tumors constitute 1% of bone tumors.
-
Bone-forming tumors: Osteosarcoma is the second most frequent malignant skull tumor after multiple myeloma, accounting for 13% of this series.
-
Cartilage-forming tumors: Chondrosarcoma is the third most common malignant bone tumor, with a frequency of 11-12.5%.
-
Connective tissue tumors: Fibrosarcoma accounts for fewer than 5% of these tumors.
-
Histiocytic tumors
Ewing sarcomas account for about 5% of these tumors.
Giant cell tumors (osteoclastomas) also account for about 5% of these tumors. [5]
-
Tumors of blood or blood vessel origin: Angiosarcomas are rare malignant tumors.
-
Squamous cell carcinomas of the temporal bone occur with a frequency of 1 case per 25,000 patients with chronic otitis.
Mortality/Morbidity
See the list below:
-
Recurrent sinusitis is a common complication of tumors affecting the sinuses.
-
If the excision is incomplete, many tumors can recur.
-
Cranial nerve compression can occur in skull-base tumors.
-
Metastasis
-
Death
-
Persistence of disease after treatment is a serious problem, since it leads to persistent morbidity; patients have a significant decrease in the quality of life prior to dying from the disease. The aim of therapy is to control the disease locally.
Race
No racial predilection exists for any malignant skull tumor.
Sex
See the list below:
-
Most malignant skull tumors have no sex predilection (except possibly metastatic disease).
-
Fibrosarcoma, Ewing sarcoma, and chordomas occur more frequently in men than in women.
Age
See the list below:
-
Bone-forming tumors and fibrosarcomas usually present in middle-aged adults.
-
Cartilage-forming tumors may present at any age, with a peak during the second decade.
-
Ewing sarcoma is a disease of childhood, whereas giant cell tumors are seen mainly between the second and fourth decades. [6]
-
Angiosarcoma can present at any age.
-
Multiple myeloma is more common in older adults.
-
Chordomas usually present in the third or fourth decade.
-
Metastatic tumors follow the pattern of the primary tumor.
-
Squamous cell carcinomas occur in the older adult, often in the sixth decade.
-
Esthesioneuroblastomas occur in young adults in their 30s and 40s.
-
Head CT scan of a 60-year-old man with a history of multiple myeloma for 2 years, showing multiple lytic lesions that involve both the inner and outer tables as well as the diploë.
-
This head CT scan shows multiple lytic lesions of the skull involving both the inner and outer tables.
