A 67-year-old man developed gradually worsening left-sided spastic hemiparesis under immunosuppressive therapy with tacrolimus after single lung transplantation. MRI revealed 2 diffusion-restricted, T2-hyperintense lesions without and with partial contrast enhancement, respectively (figure 1). Therefore, differential diagnosis mainly included progressive multifocal leukoencephalopathy, atypical CNS lymphoma, and CNS vasculitis. PET with the novel translocator protein (TSPO) tracer [18F]GE-180 showed high focal tracer uptake in both T2-hyperintense lesions. TSPO is overexpressed in activated micoglia.1 Stereotactic brain biopsy revealed tacrolimus-associated CNS vasculitis with distinct microglia activation, a rarely reported finding2 (figure 2). Our case thus suggests that TSPO PET might be a helpful tool for detection of active CNS inflammation3 in patients with suspected CNS vasculitis.
(A) MRI and [18F]GE-180-TSPO-PET reveal a contrast-enhancing lesion in the left gyrus frontalis superior. (B) Periventricular non-contrast-enhancing lesion with focal uptake in PET.
(A) Lymphocytic infiltration of small-vessel wall (arrow, hematoxylin & eosin staining). (B) Microglial activation in CD3/43 staining. (C) Reactive astrocytes in glial fibrillary acid protein staining. (D) Infiltration of CD3+ T cells. Scale: 100 μm.
Author contributions
Christoph Mahler: study design, data collection, clinical care to the patient, drafting and revising the manuscript. Marcus Unterrainer: study design, acquisition and analysis of PET scans, critical comments during manuscript revision. Carolin Muth: clinical care to the patient. Rupert Egensperger: acquisition and analysis of histopathology images. Lena Vomacka: analysis of PET scans. Simon Lindner: acquisition and analysis of PET scans. Birgit Ertl-Wagner: acquisition and analysis of MRI scans. Maximilian Patzig: acquisition and analysis of MRI scans. Peter Bartenstein: study supervision and analysis of PET scans. Nathalie Albert: study supervision and analysis of PET scans. Martin Kerschensteiner: study supervision and critical comments during manuscript revision. Tania Kümpfel: study supervision and critical comments during manuscript revision.
Study funding
No targeted funding reported.
Disclosure
The authors report no disclosures relevant to the manuscript. Go to Neurology.org/N for full disclosures.
Footnotes
Go to Neurology.org/N for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
- © 2018 American Academy of Neurology
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