Dural Follicular Non-Hodgkin Lymphoma Mimicking a Chronic Subdural Hematoma: A Case Report and Literature Review

Primary dural lymphomas are rare neoplasms that can clinically and radiologically mimic a chronic subdural hematoma, delaying accurate diagnosis; the follicular subtype is an exceptionally rare variant within this group. We report the case of a 77-year-old woman with a history of arterial hypertension who, after two ground-level falls, developed progressive right-sided hemiparesis, ipsilateral hemidysesthesia, recent memory impairment, and a left hemicranial headache. Computed tomography showed a biconvex, hypodense left fronto-parietal lesion measuring 6 × 3 cm, and magnetic resonance imaging demonstrated a T2-hyperintense lesion with dural enhancement after contrast administration, findings initially interpreted as a probable traumatic subdural hematoma versus an arachnoid cyst. Once her anemia had been corrected and she was clinically stable, she underwent craniotomy, during which the dura mater was found to be markedly thickened; histopathological and immunohistochemical studies confirmed a follicular non-Hodgkin lymphoma with an interfollicular pattern in 95% and a follicular pattern in 5%, World Health Organization grade I, CD20-positive, Ki-67 30%. The postoperative course was favorable, with improvement of the hemiparesis; she was discharged and referred to hematology, where she received chemotherapy, but died two months later. A literature review identified 14 previously reported cases of dural lymphoma mimicking a subdural hematoma, to which the present case is added. Clinical, imaging, and histopathological features suggestive of this entity are discussed, along with the main differential diagnoses of dural enhancement, including Rosai-Dorfman disease and metastatic Hodgkin lymphoma. Dural lymphoma, particularly its follicular variant, should be considered in the differential diagnosis of extra-axial lesions resembling a subdural hematoma, especially in elderly patients without a clear history of trauma or with imaging findings discordant with the expected clinical course.