Progressive multifocal leukoencephalopathy: a rare cause of cerebellar edema and atypical mass effect. A case report

Isolated cerebellar progressive multifocal leukoencephalopathy after allogeneic bone marrow transplantation: focus on imaging

INTRODUCTION

Progressive multifocal leukoencephalopathy (PML) is caused by JC virus opportunistic infection in the setting of immunodeficiency. Typical imaging features are multifocal and asymmetric lesions within supratentorial subcortical white matter in parieto-occipital regions.

CASE DESCRIPTION

A 47-year-old patient experienced a relapse of acute myeloid leukemia 21 months after hematopoietic stem cell transplantation. He also had visual impairment and magnetic resonance imaging showed an isolated cerebellar lesion without mass effect or enhancement. Common opportunistic infections and leukemic central nervous system involvement were excluded by cerebrospinal fluid (CSF) analysis. Given the worsening clinical and radiologic scenario, PML was suspected, and CSF protein chain reaction analysis was positive for JC virus.

CONCLUSIONS

Given its potential curability, PML should be thoroughly investigated in patients with hematologic neoplasms and atypical isolated cerebellar presentation.

Approach to an Intracranial Mass in Patients With HIV

PURPOSE OF REVIEW

Space-occupying lesions represent a diagnostic challenge among people with the human immunodeficiency virus, acquired immunodeficiency syndrome (HIV/AIDS). To determine the best diagnostic approach to the wide array of possible etiologies and provide a thorough interpretation of neuroimaging in order to narrow a hierarchical differential diagnosis among these patients. Given that there is no pathognomonic neuroimaging pattern in this clinical setting, we searched results from brain biopsies to best determine the etiology of commonly found lesions.

RECENT FINDINGS

Multimodal brain MRI and MRI spectroscopy (MRS) often provide the most valuable information in the study of focal masses among people with HIV/AIDS. Brain biopsy appears safe and provides high diagnostic yields in these patients. Among patients with HIV/AIDS who present with space-occupying intracranial lesions, brain MRI and MRS are useful tests. However, in cases of diagnostic uncertainty, brain biopsy is a safe procedure and should be performed. The role of metabolic studies like ²⁰¹Th-SPECT or PET is useful in the detection of primary central nervous system lymphoma.