Primary Central Nervous System Lymphoma Presenting As Chronic Subdural Hematoma: Case Report and Review of the Literature.

Primary central nervous system lymphoma (PCNSL) rarely manifests in immunocompetent patients. In such cases, these lesions may mimic more common intracranial bleeding or tumors. We present the case of an elderly patient who presented with a presumed chronic subdural hematoma (SDH); upon surgical intervention, an occult mass was discovered with no evidence of associated hematoma. Biopsy and immunohistochemistry demonstrated PCNSL. Literature review identified six other cases of PCNSL in immunocompetent adults that were initially suspected to be SDH but were finally diagnosed with PCNSL. Our literature review highlights the rarity these cases and the importance of distinguishing intracranial bleeds from PCNSL, as the latter can be treated with chemoradiation with good clinical outcomes.