Teaching NeuroImages: CNS involvement in systemic anaplastic large-cell lymphoma

An 11-year-old boy presented with acute dysarthria and right hemiparesis. Brain MRI showed multiple enhancing supratentorial lesions (figure 1, A–C). An extensive infectious workup, CSF cytology, whole-body CT, and gallium and PET scans were unremarkable. Diagnostic brain biopsy revealed reactive astrocytosis. He improved gradually with oral prednisone and azathioprine but returned 3 months later with abdominal pain, persistent vomiting, and generalized lymphadenopathy. Brain MRI showed no new lesions. A mesenteric lymph node biopsy showed hallmark cells consistent with anaplastic large-cell lymphoma (figure 2). Intrathecal methotrexate and whole-cranial irradiation resulted in radiologic resolution of lesions (figure 1, D–F). CNS involvement in CD30 ALK anaplastic large-cell lymphoma is extremely rare.1,2