Clinicopathological Spectrum of Brain Parenchymal Infections: A Retrospective Analytical Study

Brain parenchymal infections encompass a broad clinicopathological spectrum caused by bacteria, mycobacteria, fungi, and parasites, presenting non-specifically with headache, fever, seizures, focal neurological deficits, and altered sensorium. Mycobacterium tuberculosis remains the most prevalent causative organism in India, while opportunistic pathogens, including Cryptococcus, Mucor, and Zygomycetes species, are increasingly encountered in immunocompromised hosts. Although neuroimaging and microbiological investigations are integral to evaluation, imaging features frequently overlap with inflammatory and neoplastic processes, and microbiological methods are limited by suboptimal sensitivity. Histopathological examination remains indispensable for definitive diagnosis, characterising the inflammatory response and guiding therapeutic management. This study evaluates the clinicopathological spectrum of neuroparenchymal infections, excluding meningitis, at a single tertiary care centre in India.

This clinicopathological case series included 12 patients who were diagnosed with infections of the central nervous system and spine over a period of two years, from October 2023 to October 2025, at a tertiary care centre. Clinical findings, radiological diagnoses, and microbiological investigation results were collected and correlated with histopathological findings from archived paraffin-embedded blocks.

The study comprised eight females (66.7%) and four males (33.3%). The age of the study population ranged from 15 to 65 years (mean ± SD: 45.6 ± 13.2 years). Histopathological examination revealed a wide spectrum of lesions: granulomatous inflammation, three cases (25.0%); necrotising granulomatous inflammation, two cases (16.7%); xanthogranulomatous inflammation, two cases (16.7%); chronic inflammatory process, two cases (16.7%); acute-on-chronic inflammation, one case (8.3%); organised bacterial abscess, one case (8.3%); cryptococcal infection, one case (8.3%); and mucormycosis/fungal abscess, two cases (16.7%). Clinicopathological concordance was observed in 9 of 12 cases (75%). In 3/12 discordant cases (25%), histopathological findings differed significantly from the clinical and radiological diagnoses. The chi-square test was used to assess the association between the clinical and radiological impression and the final histopathological diagnosis (χ² = 9.6, p < 0.05).

This series highlights the important role of histopathological examination in the accurate diagnosis of neuroinfections. An integrated diagnostic approach, including clinical, radiological, microbiological, and histopathological findings, is essential for favourable patient outcomes.