Diagnostic Evaluation in Primary CNS Lymphoma

The diagnosis of primary central nervous system lymphoma (PCNSL) may be fraught with difficulty. After initial imaging reveals enhancing intracranial mass lesions steroids are often initiated. This leads to a decreased diagnostic yield of tumor biopsies which may be associated with delay in treatment initiation. We review a case of PCNSL treated with a very brief steroid course. Initial nondiagnostic biopsy histopathology is juxtaposed against subsequent diagnostic pathology. Imaging before and after steroids is presented, as is imaging after tumor regrowth in a noncontiguous location. Elements in the clinical history and radiographic presentation which should raise suspicion for PCNSL are reviewed. Increased understanding of the potential pitfalls surrounding PCNSL diagnosis may limit their future occurrence.