PMC4386111_01
Imaging at the time of diagnosis and throughout the course of treatment. See table 1 for timing of MRIs relative to disease course and treatment. MRIs are 1.5 T. Left-hand side: imaging on presentation. a Axial CT (bone windows) shows lytic lesions affecting the calvarium bilaterally (blue arrows). b Enhancement of the right mesial temporal lobe. This is the lesion that was biopsied (blue arrow). c, d Pontine inflammation. Post-contrast image (c) shows diffuse, patchy enhancement. FLAIR hyperintensity (d) is evident in the pons and the pituitary gland. e, f Left frontal inflammation. FLAIR image (e) shows hyperintensity with associated cystic degeneration. The latter is best seen on T1-weighted imaging (f). Right-hand side: imaging during treatment. g, h Response to cladribine (same day as completed cycle No. 3). Improvement in enhancement (g) and FLAIR hyperintensity (h) versus images c and d. i, j Response to IVIG (same day as completed cycle No. 2). Enhancement remains stable. Brainstem FLAIR hyperintensity improved (j vs. h). One month after the most recent cycle of cladribine. k, l Disease stable (no treatment for 30 days). Some worsening of pontine enhancement, although not as marked as when the patient first presented (k vs. c).
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F1
Brain images on presentation are shown on the left in fig. 1a-f. Two weeks after the initial treatment, the brainstem showed some improvement in the degree of FLAIR hyperintensity (fig. 1i, j). An MRI 1 month after a second course of IVIG showed these changes to be stable overall, with some increase in pontine enhancement (fig. 1k, l).
Left frontal bone biopsy. Images labeled top to bottom. a Magnification is x40. HE staining. Langerhans cells are visible as large, oval, mononuclear cells with coffee-bean-shaped nuclei and moderately abundant, slightly eosinophilic cytoplasm. The nucleus is prominent with fine chromatin and thin nuclear membranes with grooved, folded, or indented nuclear contours, imparting a 'twisted towel' or 'coffee bean' appearance. There are few cytoplasmic vacuoles, little or no phagocytic material and no dendritic processes. Many such cells are seen and 2 good examples are highlighted (blue arrows). b CD1a staining shows a diffuse uptake by Langerhans cells. c S-100 staining for Langerhans cells is strongly positive.
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F2
This is shown in figure 2.
Right temporal lobe biopsy. HE staining. Magnification is x40. Mildly hypercellular and gliotic gray matter with focal reactive changes. No neoplasia is seen.
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F3
The biopsy is shown in figure 3.