Pontocerebellar angle aspergillosis: clinical and radiological findings.

Introduction: Cerebral aspergillosis is a rare and severe condition mostly affecting immunocompromised patients. The lesions are usually intra-axial and supratentorial; several radiologic patterns have been reported. Case report: A 65-year-old patient with chronic lymphocytic leukemia presented with fever, headache, and a pontocerebellar syndrome. A brain magnetic resonance imaging (MRI) showed a ring-enhancing left pontocerebellar mass consistent with an infectious disease. Despite broad-spectrum antibiotic therapy, the patient worsened. A follow-up MRI examination disclosed a concomitant acute ischemic lesion in the ipsilateral thalamus and an irregular narrowing of the posterior cerebral artery close to the lesion. A retrospective analysis of the first MRI revealed a small mesencephalic ischemic lesion, contiguous to the extra-axial pontocerebellar mass. At surgical inspection the mass was found to be an extra-axial granuloma, with purulent components, attached to the petrous-tentorial angle, surrounded by a thick capsule. The lesion was only partially removed because of the tight relationship with the leptomeninges of the brain stem. Cerebral aspergillosis was the final histologic and microbiological diagnosis. Conclusion: In immunocompromised patients, the coexistence of an infectious lesion with involvement of contiguous vessels and consequent ischemic infarction should raise the suspicion of aspergillosis, even in unusual locations such as the pontocerebellar angle.