血管内大 B 细胞淋巴瘤 (IVLBCL) 是一种非常罕见的侵袭性非霍奇金 B 细胞淋巴瘤亚型，其特征是克隆 B 淋巴细胞的血管内增殖，通常与肺部和皮肤疾病相关，少数情况下与中枢神经系统 (CNS) 受累相关。脑成像结果通常是非特异性的，有证据表明多处血管闭塞和中风是非特异性的多灶性异常。我们报告了一个极其罕见的 IVLBCL 病例，患者患有不明原因的炎症综合征，伴有 B 症状和快速进行性神经功能障碍，MRI 上可见多灶性出血性和肿胀性脑损伤。我们建议，在这种临床情况下，肿胀和出血性病变的存在应引起对 IVLBCL 的怀疑，并导致决定进行活检，尽管如此，活检仍然是诊断的金标准。

Intravascular large B cell lymphoma (IVLBCL) is a very rare subtype of aggressive non-Hodgkin B cell lymphoma characterized by intravascular proliferation of clonal B lymphocytes, classically associated with pulmonary and cutaneous disease and, less frequently, with central nervous system (CNS) involvement. Brain imaging findings are usually non-specific, with evidence of multiple vascular occlusions and stroke as non-specific multifocal abnormalities. We present an exceptionally rare case of IVLBCL in a patient with unexplained inflammatory syndrome with B symptoms and rapidly progressive neurological impairment, with multifocal hemorrhagic and tumefactive brain lesions seen on MRI. We suggest that in this clinical setting, the presence of tumefactive and hemorrhagic lesions should raise suspicion for IVLBCL and lead to the decision to perform a biopsy, which, nonetheless, remains the diagnostic gold standard.