Progressive conus medullaris lesions are suggestive of intravascular large B‐cell lymphoma

Abstract Background and purpose Spinal cord lesions are observed in 40% of all central nervous system lesions in intravascular large B‐cell lymphoma (IVLBCL). However, because IVLBCL is a very rare disease, its clinical features are not well defined, which may delay appropriate diagnosis and treatment, whilst the acute to subacute course of brain lesions in patients with IVLBCL is well established. Therefore, this study aimed to clarify the clinical features of spinal cord lesions in patients with IVLBCL. Methods The medical records of patients with IVLBCL admitted to our hospital between 2010 and 2020 were searched. The inclusion criteria were preceding neurological symptoms without non‐neurological symptoms and pathologically confirmed IVLBCL in various organs. Clinical features of spinal cord involvement in patients with IVLBCL were assessed and distinguished from those of brain involvement. Results Sixteen consecutive patients with IVLBCL were divided into two groups: six patients with spinal involvement (spinal cord type) and 10 patients with brain involvement (brain type). In the spinal cord type, four patients had chronic progression and two had subacute progression. Acute progression (0% vs. 80.0%) and sudden onset (0% vs. 50.0%) occurred significantly less frequently in the spinal cord than in the brain. All spinal cord lesions involved the conus medullaris. Conclusions Spinal cord involvement in IVLBCL has a predominantly chronic progressive course that is exclusive to brain involvement. Conus medullaris lesions are suggestive of IVLBCL and are useful for early and accurate diagnosis and treatment.