Surgical management of intracranial fungal masses

Background: Intracranial fungal masses (IFMs, granulomas and abscesses) are uncommon lesions, infrequently encountered by neurosurgeons. There is no conclusive evidence on the ideal surgical management of these lesions.
Aims: To summarize the recent literature on the prevalence, presentation, surgical management and outcome of patients with IFMs.
Materials and Methods: The recent published literature was searched using standard search engines (PubMed and Google) for articles reporting on the databases and surgical management of IFMs. A special effort was made to include publications from Indian centers.
Results: Intracranial fungal masses were rarely seen even in major neurosurgical centers in India with a prevalence of around one to two per year. While most patients with IFM have immunosuppressed states, nearly 50% of patients with IFMs (especially in India) have no obvious predisposing causes and are apparently immunocompetent. The clinical presentation could be categorized into three groups: 1. Involvement of the cranial nerves 1 to 6 with orbital and nasal symptoms. 2. Focal neurological deficits due to involvement of any part of the neuraxis; and 3. "Stroke-like" presentation with sudden onset of hemiparesis. Based on the presence or absence of radiological evidence of paranasal sinus disease, IFMs were classified into two types: 1. Rhinocerebral type; 2. Purely intracranial type that was further divided into a. intracerebral or b. extracerebral forms. Aspergillus species was the commonest fungal organism causing IFMs but a number of other fungi have been reported to cause IFMs. Surgery for IFMs can be of different types, namely 1. Stereotactic procedures; 2. Craniotomy; 3. Shunt surgery; and 4. Treatment of fungal aneurysms. Generally, radical surgery is advocated for IFMs but there is no unanimity regarding the radicality of the excision especially for the rhinocerebral form of the disease. Surgery should always be followed by antifungal therapy for prolonged periods. Mortality and morbidity in patients with IFMs is very high and ranges from 40-92%. Immunosuppressed patients with IFMs and those in whom the diagnosis is delayed have the highest mortality rates, with immunocompetent patients with the rhinocerebral form of the disease having the best outcome.
Conclusions: There should be a high index of suspicion for IFMs not only in patients with known risk factors for the development of fungal infections but also in immunocompetent patients in India. Intraoperative pathological diagnosis should be obtained in any patient suspected to have an IFM and tissue should be processed for fungal cultures. Prompt diagnosis, radical and safe surgery and aggressive and prolonged treatment with anti-fungal agents may lead to a better outcome especially in immunocompetent patients.

Keywords
Brain, fungal abscess, fungal granuloma, outcome, stereotactic surgery, surgery