Meningiomas: clinical correlates, skull x-ray, CT and pathological evaluations

To assess the frequency and the diagnostic performance of plain skull x-ray and and CT of meningiomas.

All pathologically diagnosed intracranial meningiomas in patients seen at Tikur Anbessa Hospitals were reviewed.

Between December 1999 and July 2004 there were 25 histologically diagnosed cases of meningioma at the Tikur Anbessa Hospital (TAH). The duration of symptoms was ranging from 0.5-10 yrs. (mean 2.4 +/- 2.1 yrs) and age ranging from 21-57 yrs (mean age of 49.3 +/- 10 yrs.) with M:F ratio of 1.2:1. Blurring of vision was the commonest clinical presentation. Clinical correlates, skull x-rays, computerized tomographic results and pathology are evaluated. Plain skull x-ray findings were normal in 12/23 (52%); 10/23(43%) of the cases had non-specific sellar changes of raised intra-cranial pressure. Twenty-three of the 25 meningiomas had CT scanning done, and CT diagnosed 17/23 (74%) meningiomas correctly. Two meningiomas were unusual in location: one was intranasal and the other was intra-ventricular. Parasellar tumors were frequent sites of misdiagnosis. The commonest locations were parasellar and cerebral convexity, each accounting for 6/25 (24%) of the cases. The commonest CT observation was intense and homogeneous enhancement 15/23 (65%). Meningothelial meningioma was the commonest cellular type accounting for 11/25 (46%) of the pathologies followed by the transitional 4/25 (16%) and the atypical and psammomatous types, each with equalfrequency, 3/25 (12%).

CT scan had a diagnostic accuracy of 83%, sensitivity of 74%, specificity of 95%, positive predictive value (PPV) of 95%, and negative predictive value (NPV) of 75%. Statistical analysis verifies the pre-operative reliability for diagnosing meningiomas by CT scanning.