Case Report: Intravascular large B-cell lymphoma presenting with cauda equina syndrome: a rare case and diagnostic dilemma.

OBJECTIVE: To investigate the clinical and diagnostic characteristics of intravascular large B-cell lymphoma (IVLBCL) presenting primarily as cauda equina syndrome (CES), analyze factors contributing to diagnostic delay, and evaluate the diagnostic value of minimally invasive biopsy. METHODS: We report a case of IVLBCL that initially presented with CES. The diagnostic process was reviewed by analyzing serum biomarkers and pathology from a random skin biopsy (RSB) that included subcutaneous fat tissue. Additionally, a literature review was conducted via the PubMed database (2005-2025), which identified and analyzed 10 additional cases of IVLBCL with CES as the initial manifestation. Imaging features, clinical symptoms, and time-to-diagnosis were synthesized across these cases. RESULTS: In the present case, the patient presented with progressive lower extremity weakness, saddle anesthesia, and sphincter dysfunction, while early spinal MRI findings were unrevealing. Diagnostically, markedly elevated lactate dehydrogenase (LDH) and interleukin-10 (IL-10) provided key clues, and definitive diagnosis was achieved via a multi-site incisional RSB including subcutaneous fat. In comparison, the 10 literature-retrieved cases (n = 11 in total) universally demonstrated typical CES but posed significant diagnostic challenges due to the non-specificity of early symptoms and high heterogeneity on initial spinal MRI, which frequently lacked direct space-occupying evidence or appeared entirely normal. CONCLUSION: Clinicians should maintain a high index of suspicion for IVLBCL in patients presenting with CES when initial imaging findings fail to reflect the clinical severity, particularly when accompanied by systemic laboratory abnormalities such as elevated LDH. While serum IL-10 may serve as a potentially useful adjunctive biomarker to raise diagnostic suspicion, prompt initiation of a RSB enables early detection of this disease and minimizes diagnostic delays.