What is the definition of meningioma?
Meningiomas are extra-axial meningothelial tumors that arise from the arachnoidal cells around the brain and spinal cord. They are the most common extra-axial dural tumor, which affects women more than men, between the ages of 40 and 70; they are sporadic in children. Most meningiomas are benign and classified as WHO I. A few are categorized as WHO II or III, indicating malignancy.
Where are the locations of intracranial meningiomas?
Intracranial meningiomas arise in the following locations: convexity, parasagittal (which includes falcine meningiomas), sphenoid, and middle cranial fossa, frontobasal, posterior fossa (including the tentorium cerebelli, cerebellar convexity, cerebellopontine angle, and clivus), intraventricular, orbital, and ectopic.
What are the characteristics of clival meningiomas?
Its location close to the midline of the clivus characterizes clival meningiomas. It is intimately associated with the brainstem, vertebral arteries, basilar artery, perforating arteries, and multiple cranial nerves.
What are the symptoms of clival meningiomas?
The size of the tumor determines the symptoms of clival meningioma, and they occur as a result of compression of surrounding structures. The symptoms include headache, seizures, unilateral hearing loss, facial sensory disturbances, or trigeminal neuralgia. These patients may present other symptoms like ataxia, vertigo, difficulty walking, nausea, vomiting, vision problems, blurry vision, optic disc swelling (papilledema), painful swallowing (dysphagia), sensory problems, and muscle weakness.
What are the imaging features of clival meningiomas?
The imaging features of clival meningiomas are similar to those of typical meningiomas, showing a sessile or lentiform, well-circumscribed mass with a broad-based dural attachment. It usually demonstrates hyperdensity or isodensity on non-contrast CT and iso to hypointensity on both T1 and T2-weighted MR images. Some meningiomas contain calcification, and CT is best to see it. On MRI, calcification presents as areas of low signal intensity on susceptibility-weighted images (GRE and SWI). Uniform enhancement and the enhancing-thickened dural tail is common after contrast administration. Meningiomas usually cause hyperostosis in the underlying bones, and rarely it can cause osteolysis. Clival meningiomas have a close relationship with the brainstem, and large tumors can displace it or encase the vertebral or basilar arteries. MR spectroscopy may demonstrate high choline: creatine (Cho-Cr) ratio, and also high alanine peak, and a low N-acetyl aspartate (NAA) peak. Alanine-creatine ratios are useful in distinguishing meningiomas from other intracranial tumors.
Which are the treatment for clival meningiomas?
The definitive treatment for meningiomas is complete surgical resection of the tumor. Despite the development of modern surgical technology and multimodality therapy, the surgical treatment of clival meningiomas continues to be a challenge for neurosurgeons because of their difficult anatomical location. Adjuvant radiotherapy or stereotaxic radiosurgery may be employed in cases of incomplete resection or for cases that are associated with post-surgical complications.
Pathology
Macroscopy: In formalin, several irregular, elastic, brownish-brown tissue fragments, measuring the most extensive 1.4 x 0.6 x 0.5 cm. The cuts are compact, of the same color.
Microscopy: There are indistinct cytoplasmic boundaries, cellular whorls, mixed cellular spindling, and a fascicular or storiform architecture, consistent with WHO I transitional meningioma, with bone infiltration.
Conclusion: Excision product, intracranial tumor (clivus) - transitional meningioma (WHO I).