Histopathological Spectrum and Adverse Morphologic Features of Meningiomas in a Low-Volume Tertiary Centre: A Five-Year Retrospective Case Series

Background: Meningiomas comprise a morphologically diverse group of primary central nervous system tumours. Although many exhibit indolent behaviour, individual lesions vary in proliferative activity and invasive potential. Histopathological assessment therefore remains important for characterising tumour morphology and identifying adverse microscopic features, particularly in settings where diagnosis is centred on routine histology. Objective: To describe the histopathological spectrum and adverse morphologic features of meningiomas diagnosed over five years in a low-volume tertiary centre in southeastern Nigeria. Methods: A retrospective descriptive case series was conducted at Nnamdi Azikiwe University Teaching Hospital, Nnewi, Nigeria, covering January 2021 to December 2025. All histologically confirmed meningiomas diagnosed during the study period were included. Archived haematoxylin and eosin-stained slides were reviewed, and demographic and pathological variables were extracted from departmental records. Histological assessment focused on tumour subtype, mitotic activity, brain invasion and tumour necrosis. Data were analysed descriptively using frequencies, percentages, mean, standard deviation and range. Results: Ten meningiomas were identified. Patients were aged 24 to 73 years, with a mean age of 51.6 ± 14.9 years, and eight of the ten patients were female. Meningothelial morphology was the most frequent subtype, occurring in six cases, while transitional and papillary patterns each occurred in two. The sphenoid wing was the most frequently recorded anatomical site, accounting for four cases. Mitotic activity was lower in meningothelial and transitional tumours and markedly higher in the papillary tumours. Brain invasion was present in both papillary tumours, while tumour necrosis was identified in one papillary case. Conclusion: The series demonstrated a predominance of meningothelial morphology, with adverse histological features concentrated within the papillary tumours. The combination of increased mitotic activity, brain invasion and necrosis highlights the importance of systematic assessment of proliferative and invasive features alongside architectural subtype in routine meningioma histopathology. Larger multi-centre studies are needed to characterise these patterns more robustly across Nigerian and other sub-Saharan African settings.