Neurological Masquerades of Diffuse Large B-cell Lymphoma: A Case Mimicking Motor Neurone Disease

Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma (NHL) and typically presents with lymphadenopathy, constitutional symptoms, or extranodal disease.Neurological presentations are uncommon and may mimic primary neurological disorders, which creates significant diagnostic challenges.A 67-year-old woman presented with progressive lower back pain, paraesthesia affecting all four limbs that left her bed-bound, faecal incontinence, dysphagia, weight loss, and evolving neurological deficits, including left-sided facial weakness and asymmetric tetraparesis predominantly affecting the left side.Initial neuroimaging demonstrated no acute intracranial pathology and no evidence of spinal cord compression.Electromyography (EMG) revealed widespread active and chronic denervation, which suggested an anterior horn cell disorder or motor neurone disease (MND).However, the presence of sensory symptoms, constitutional features, and progressive clinical deterioration prompted further investigation.CT of the chest, abdomen, and pelvis identified cervical and retroperitoneal lymphadenopathy.Ultrasound-guided lymph node biopsy confirmed DLBCL.Cerebrospinal fluid (CSF) analysis did not demonstrate definitive evidence of central nervous system (CNS) lymphoma.After six cycles of polatuzumab vedotin, rituximab, cyclophosphamide, doxorubicin, and prednisolone (Pola-R-CHP), the patient achieved complete metabolic remission and showed substantial improvement in her neurological symptoms.This case highlights the importance of maintaining a broad differential diagnosis in patients presenting with atypical neurological syndromes.DLBCL may rarely present with neurological features that mimic MND.Although a definitive paraneoplastic neurological syndrome (PNS) could not be established, a possible paraneoplastic neurological process was considered.Recognition of systemic red-flag features, such as weight loss and lymphadenopathy, was pivotal in reaching the correct diagnosis.