case_images: PMC3114311_01
case_images: PMC3114311_02
case_images: T1-weighted MRI scans with contrasts showing (a) axial, (b) coronal, and (c) sagittal images of the lesion
case_images: SNI-2-57-g001.jpg
case_images: PMC3114311_02_SNI-2-57-g001.jpg
case_images: F1
case_images: Of concern was adjacent meningeal enhancement, but there was no abnormal signal identified within the brain parenchyma itself [Figure 1].
case_images: PMC3114311_03
case_images: Immunohistochemical stains of the biopsied tissue. (a) CD68, (b) S100+, and (c) CD1a+ stains (original magnification, x100)
case_images: SNI-2-57-g002.jpg
case_images: PMC3114311_03_SNI-2-57-g002.jpg
case_images: F2
case_images: For the first case, the intraoperative cultures were negative and the pathological study demonstrated a lesion with histiocytic and eosinophilic infiltrate, which stained positive for CD1a (+) and S100 (+) [Figure 2].
case_images: Electron micrograph of the biopsied tissue. Electron micrograph was of compromised quality as the thin sections were recovered from fixed paraffin embedded tissue. Membrane bound electron lucent vesicles suggestive of a component of Birbeck granules are seen within the histiocytes. The typical cross-striated rod domain is not as evident
case_images: SNI-2-57-g003.jpg
case_images: PMC3114311_03_SNI-2-57-g003.jpg
case_images: F3
case_images: EM studies revealed atypical inclusion bodies consistent with pathognomonic Birbeck granules [Figure 3].