A 10-year-old Caucasian boy was admitted to the hospital with a 3-month history of headache, vomiting, ataxia, and right amaurosis. A magnetic resonance imaging (MRI) showed a solid, expansive, parasagittal mass in the right parietal hemisphere that extended sagitally to include the optical chiasm. The lesion was considered unresectable. Histology and immunophenotyping of biopsy tissue revealed characteristics of peripheral T-cell lymphoma. No other anatomical region, including bone marrow, was compromised. Primary T-cell lymphomas of the central nervous system are rare, especially in childhood. Here, we describe the rapidly deteriorating and fatal clinical course of a boy with a primary T-cell lymphoma in the central nervous system.