Primary Central Nervous System Lymphoma with Associated Demyelination and Creutzfeldt Astrocytes.

A previously healthy 54-year-old woman presented with weight loss, progressive weakness that was more pronounced on the left side, and intermittent occipital headaches. Imaging studies showed multiple enhancing lesions along the white matter, compatible with a demyelinating process. The patient's previous history included relapsing-remitting symptoms of weakness over the past 3 years. A stereotactic brain biopsy showed histological features of demyelination with an associated population of neoplastic lymphoid cells. These unusual findings raise the question of whether demyelinating disease preceded the development of primary CNS lymphoma (PCNSL), or whether PCNSL induced demyelination. Although rare, cases of "sentinel lesions" heralding the diagnosis of PCNSL have been reported. This case emphasizes the importance of having a high index of suspicion of PCNSL in the setting of suspected demyelinating lesion in an adult patient.