A retrospective histomorphologic study of meningeal masses in Benin City, Nigeria

Abstract

Background: The rarity of many histologic entities and the common discordance between histologic appearance and biologic behaviour make the diagnosis of meningeal masses challenging. Except for a few common entities like meningioma and meningeal metastases, data on the prevalence of meningeal mass lesions is limited, and most exist as case reports and small case series. This study presents the pattern of meningeal masses in our environment, in the hope of adding to knowledge and awareness of the differential diagnoses of meningeal masses in our environment.

Materials and methods: A retrospective study of meningeal masses histologically diagnosed at the the University of Benin Teaching Hospital, Benin city, Nigeria, based on clinical, demographic and histomorphologic data obtained over a 15-year period.

Results: Total of 140 meningeal masses; 137 neoplastic and 3 non-neoplastic mass lesions. Ages ranged from 3-86 years. Mean age was 45.85 ± 18.16 years. There were 52 males and 88 females with an overall male-female ratio of 1:1.7; but non-meningothelial tumours were more common amongst males. Most common tumour was Meningioma (78.6%), then metastatic tumours (15%), non-meningothelial mesenchymal tumors (4.3%), and hypertrophic pachymeningitis (2.1%). Meningioma, hemangioblastoma and embryonal rhabdomyosarcoma were the most common tumours in children.

Conclusion: Rare histologic entities arising in the meninges, can easily be overlooked in the differential diagnosis of meningeal mass lesions, while the common ones like meningioma and meningeal metastases, are at risk of becoming ‘waste basket’ or ‘safety net’ diagnoses for meningeal tumours. There is need for continuous evaluation and audit of histological diagnoses of meningeal tumours to avoid missing the rare entities that may occasionally be encountered.