Primary intracranial plasmablastic lymphoma with intradural extramedullary metastasis: a case report.

Background: Primary central nervous system plasmablastic lymphoma (PCNSPBL) represents an exceptionally rare and aggressive subtype of diffuse large B-cell lymphoma (DLBCL), characterized by its distinct immunophenotypic profile and predilection for immunocompromised individuals. Accurate preoperative diagnosis remains challenging due to the nonspecific radiological features observed on conventional magnetic resonance imaging (MRI), necessitating comprehensive histopathological evaluation for definitive diagnosis. While intracranial involvement of PBL has been documented in the literature, intraspinal metastasis of this malignancy has not been previously reported. This study presents a novel case of PCNSPBL with concurrent spinal cord metastasis in an elderly male patient, with a detailed analysis of advanced neuroimaging characteristics that may aid in the diagnostic evaluation of this rare entity.

Case presentation: A 52-year-old male patient presented to our institution with left-sided limb weakness. Laboratory investigations revealed positive Epstein-Barr virus-encoded small RNA (EBER). Conventional MRI demonstrated a mass lesion with a clear anatomical relationship to the inferior horn of the right lateral ventricle, presenting as compression and stenosis of the right ventricle. Due to the mass effect, the patient underwent surgical resection of the right temporal lobe lesion, with histopathological examination confirming the diagnosis of plasmablastic lymphoma.

Conclusions: This report represents the first documented case of PCNSPBL with intradural extramedullary metastasis, underscoring the diagnostic challenges associated with this rare malignancy. Advanced neuroimaging techniques, including functional MRI, serve as valuable complements to conventional MRI in the diagnostic workup. Early and accurate diagnosis of PBL is critical for timely intervention, and further studies are warranted to establish standardized imaging protocols for this rare entity.