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Abstract
Multiple benign and malignant tumors originate from the base itself or from structures below or above it. These tumors may invade the base through the weak cribriform plate of ethmoid bone.
Although skull base tumors are derived from different embryological tissues, including glandular, epithelial, neural, ectodermal, and mesenchymal compartments. Meningiomas was the commonest while, many other neoplasms were encountered as haemangioma, fibrous histiocytoma and olfactory schwannoma.
Anterior skull base neoplasms were more common in females, with the mean age incidence for meningiomas was 50.2 years and 34.3 years for non meningiomatous neoplasm.
In most cases the initial symptom was headache which was typical of increased intracranial pressure. Some tumors especially olfactory groove meningiomas were discovered late when the tumor size becomes large causing compression of some important structures as optic nerve and chiasm. Diminished vision either unilateral or bilateral with or without field defect, was another important symptom especially in deep sphenoid and tuberculum sellae meningiomas. Anosmia was another important symptom unique to olfactory groove meningioma and it passed unnoticed in some patients. Less common clinical symptoms were frontal manifestations, diplopia, focal neurological deficits, and nasal problems in tumors arising from the nasal sinuses.
Brain MRI was the most useful diagnostic modality. It helps as well in differential diagnosis and follows up of patients having anterior skull base extra-axial neoplasms. CT scan is more sensitive in demonstrating skull base bony details.
Preoperative angiography delineates the displacement and narrowing of the internal carotid artery or its branches. MRA is non invasive and also can delineate the position and state of the neighboring vessels.
Midline anterior skull base neoplasm extending to suprasellar area can be approached using anterior transcranial corridor. Tumors originated from the paranasal sinus region and extend to the face and into the skull base can also be dealt with using an anterior transfacial approach. While the anterolateral cranial corridor is the most common route through which sphenoid ridge, suprasellar and olfactory groove tumors can be approached.
The use of microsurgical techniques considerably widens the possibilities for total surgical excision with decompression of vital neurovascular structures.
The only definitive cure for meningiomas is complete surgical resection. Malignant tumors need early radical resection via combined approaches with safety margins. Postoperative radiotherapy is helpful in these cases. Newer techniques in reconstruction, improvement of neuroanaesthesia, adjuvant therapy, intensive postoperative care and rehabilitation methods has dramatically improved the outcome of these cases.