MENINGIOMA-02 A RADIOLOGY- PATHOLOGICAL CORRELATION OF HYPEROSTOSIS AMONG PATIENTS WITH INTRACRANIAL MENINGIOMAS AT THE KENYATTA NATIONAL HOSPITAL.

BACKGROUND: Meningiomas account for 34.4% of all central nervous system (CNS) neoplasms in Kenya. Hyperostosis has been described in 25% to 44% of meningiomas. According to Simpson et al, complete bony removal is associated with a 9% recurrence rate over a ten year period. Prior traumatic injury, activation of osteoblastic cells, synthesis of bone fragments and vascular abnormalities brought on by the neoplasm are all factors that may contribute to hyperostosis. The purpose of this study was to ascertain whether hyperostosis in cases of meningiomas are solely attributed to tumor invasion. MATERIALS AND METHODS: This prospective study included all patients with a diagnosis of meningioma with radiological evidence of hyperostosis. Preoperatively, a computed tomography (CT) scan was done by a consultant radiologist in all patients and reviewed by two neurosurgeons for associated bony hyperostosis. Intra-op, a sample of the bone measuring 2cm by 2cm by 2cm displaying features of hyperostosis was harvested. Bone samples were decalcified with 10% formic acid. A consultant neuropathologist thereafter microscopically evaluated the samples to check for bone invasion. RESULTS: Radiological evidence of hyperostosis was present in 22 (61.1%) patients out of 36 patients. Out of the 22 patients, female patients were 17(77.3%) while male patients were 5(22.7%). The median age of the patients at the time of surgery was 45.5 years (range 20-65 years; mean 44.3 ± 11.9 years). On histopathological examination, Meningothelial meningioma was the most common variant (59%). Microscopic tumor invasion of the bone was seen in 13 (59.1%) patients. CONCLUSION: A significant number of patients with radiological hyperostosis had tumor invasion of the bone. The findings of this study show that one should remove the bone flap whenever possible in order to achieve total excision of the tumor, reduce recurrence rates and perform titanium mesh/ hydroxypartite cement cranioplasty for calvarial reconstruction.