Background <p>Longitudinal transverse myelitis (LETM) is characterized by a spinal cord lesion that extends more than three vertebrae. While neuromyelitis optica is the predominant cause of LETM, other potential causes include inflammatory, autoimmune, infectious, neoplastic, paraneoplastic, vascular, and metabolic etiologies. Among the autoimmune etiologies, the incidence of LETM in patients with rheumatoid arthritis (RA) is extremely rare. This report presents a case of idiopathic LETM in a patient diagnosed with RA.</p> Case presentation <p>A 47-year-old female with RA presented with acute left lower limb weakness and numbness for four days, accompanied by urine incontinence. Additionally, she experienced neck and back pain and loss of sensation in the lower body for two months. No recent trauma or constitutional symptoms were reported. MRI of the spine revealed a longitudinally extensive transverse myelitis. Laboratory workup did not reveal any signs of demyelinating or infectious disease. The patient’s condition significantly improved after treatment with corticosteroid pulse therapy and plasmapheresis.</p> Conclusion <p>The occurrence of LETM in RA is rare. In the case presented, we could not determine whether LETM was a neurological manifestation of RA or merely a coincidental association. However, further research is necessary to clarify the relationship between RA and LETM, as well as the underlying pathogenesis.</p>