Case Report: Diffuse large B-cell lymphoma presenting predominantly with spinal cord involvement: a series of three cases confirmed by abdominopelvic lymph node biopsy.

Purpose: Secondary central nervous system lymphoma (SCNSL) presenting with predominant spinal cord involvement is rare and often misdiagnosed. This case series aims to describe the clinical characteristics, diagnostic challenges, and the critical role of lymph node biopsy in confirming SCNSL in patients with spinal cord manifestations, with the goal of improving diagnostic accuracy for diffuse large B cell lymphoma (DLBCL) involving the spinal cord. Methods: We report three cases of SCNSL with predominant spinal cord involvement, all confirmed as DLBCL by abdominopelvic lymph node biopsy. Initial presentations included lower extremity numbness, weakness, and urinary disturbances. Clinical and imaging data were reviewed, along with diagnostic workup and histopathological findings. Results: All three patients were initially misdiagnosed with myelitis or demyelinating disorders and showed only transient improvement following corticosteroid and immunomodulatory therapy. Spinal MRI revealed abnormal cord signals, while contrast-enhanced abdominal CT and whole-body PET/CT identified hypermetabolic lesions in abdominopelvic lymph nodes. Definitive diagnosis was established by pathological examination of lymph node biopsy specimens, confirming DLBCL. Conclusion: SCNSL with isolated or predominant spinal cord involvement presents with nonspecific symptoms and can mimic inflammatory myelopathies, leading to diagnostic delays. Lymph node biopsy plays a pivotal role in establishing the diagnosis. Increased awareness of this atypical presentation may facilitate earlier recognition and timely management of DLBCL with spinal cord involvement.