For patients with a spinal cord syndrome associated with nonspecific myelopathy, it is important to search for a tumor. Among tumors of the central nervous system (CNS) with possible initial spinal cord involvement, lymphoma is a very rare etiology, but one that should not be missed because of the expected therapeutic benefit. These lymphomas may present as isolated spinal cord lesion(s) or with concurrent brain lesion(s). The diagnostic approach is slightly different from that of other primary spinal cord tumors. CSF analysis is essential, as it can be highly informative and may modify the diagnostic procedure. We report the cases of four patients who had a primary CNS lymphoma with initial spinal cord involvement (PCNSL-SC). To our knowledge, no case of PCNSL with secondary spinal cord involvement has been described in the literature, but underdiagnosis is probable. Concerning our patients, considerable differences were noted concerning means used to establish diagnosis, tumor chemosensitivity, and long-term outcome, an observation suggesting that PCNSL-SC would be a heterogeneous disease [1].