Primary dural lymphoma mimicking a chronic epidural hematoma. Differential diagnosis of two rare conditions

Primary Central Nervous System Lymphoma (PCNSL) is an extranodal Non-Hodgkin Lymphoma (NHL) that arises in the brain parenchyma, eyes, meninges, or spinal cord in the absence of lymphoma outside of the CNS at the time of the diagnosis. Pure primary leptomeningeal lymphoma (PLML) is a subtype of PCNSL, it represents less than 0.1% of all NHL. Primary dural lymphoma (PDL) is a subentity of PLML and it is described as dura mater involvement with no systemic disease. PDL represents less than 1% of all brain lymphomas. The diagnosis of PDL is very difficult because the imaging appearance usually is of an extra-axial mass mimicking a meningioma [1] or a hematoma [2,3]. We report a case of PDL with immunophenotype of chronic lymphocytic leukemia/small lymphocyte lymphoma (CLL/SLL), which was initially clinically diagnosed as a chronic extradural hematoma (EDH). In literature this is the third case of PDL mimicking hematoma and the seventh case of primitive CLL/SLL of the dura.