<scp>E</scp>pstein‐<scp>B</scp>arr virus‐positive diffuse large <scp>B</scp>‐cell primary central nervous system lymphoma associated with organized chronic subdural hematoma: A case report and review of the literature

<jats:p>We here report on a rare case of <jats:styled-content style="fixed-case">E</jats:styled-content>pstein‐<jats:styled-content style="fixed-case">B</jats:styled-content>arr virus (<jats:styled-content style="fixed-case">EBV</jats:styled-content>)‐positive diffuse large <jats:styled-content style="fixed-case">B</jats:styled-content>‐cell lymphoma (<jats:styled-content style="fixed-case">DLBCL</jats:styled-content>) detected in both brain parenchyma and in an organized chronic subdural hematoma (<jats:styled-content style="fixed-case">OCSH</jats:styled-content>). A 96‐year‐old man diagnosed with asymptomatic <jats:styled-content style="fixed-case">OCSH</jats:styled-content> in the left frontal convexity was referred to our hospital because of a de novo mass lesion just beneath the <jats:styled-content style="fixed-case">OCSH</jats:styled-content> on contrast‐enhanced magnetic resonance imaging. The size of the <jats:styled-content style="fixed-case">OCSH</jats:styled-content> remained stable. We diagnosed the lesion as a malignant tumor. At surgery, the organized hematoma and the soft fragile tumor were removed. Histological examinations revealed pleomorphic lymphoid cells not only in the brain tissue but also in the <jats:styled-content style="fixed-case">OCSH</jats:styled-content> component with tumor necrosis, and these were immunopositive for <jats:styled-content style="fixed-case">B</jats:styled-content>‐cell markers. <jats:italic>In situ</jats:italic> hybridization revealed positive signals for <jats:styled-content style="fixed-case">EBV</jats:styled-content>‐encoded small <jats:styled-content style="fixed-case">RNAs</jats:styled-content>, consistent with <jats:styled-content style="fixed-case">EBV</jats:styled-content>‐positive <jats:styled-content style="fixed-case">DLBCL</jats:styled-content>. Since the membranes of the subdural hematoma were fibrous and the tumor progression resulted in necrosis of the tumor, the <jats:styled-content style="fixed-case">DLBCL</jats:styled-content> may have originally developed in the <jats:styled-content style="fixed-case">OCSH</jats:styled-content> and infiltrated into the brain parenchyma. We believe that this rare case provides crucial information for the understanding of <jats:styled-content style="fixed-case">DLBCLs</jats:styled-content> associated with <jats:styled-content style="fixed-case">OCSH</jats:styled-content>.</jats:p>