Longitudinally extensive transverse myelitis after pembrolizumab and lenvatinib therapy for a rare subtype of renal cell carcinoma: A case report.

Immune checkpoint inhibitors (ICIs) have revolutionized oncology, shifting the approach from directly targeting tumor cells to enhancing the immune response of the host towards tumor cells by blocking inhibitory receptors or ligands. The present report describes the case of a 26-year-old female patient diagnosed with a rare subtype of renal cell carcinoma (RCC), transcription factor E3-rearranged (t)RCC, who presented with progressing motor weakness of the lower extremities, along with urinary and fecal incontinence, which had begun 3 days prior to admission. A diagnosis of longitudinally extensive transverse myelitis (LETM) was made, resulting in the administration of methylprednisolone and intravenous immunoglobulin. Subsequently, the condition of the patient markedly improved. LETM, a rare and potentially life-threatening condition, manifests through symptoms such as pain, sensory deficits, motor impairments and disturbances in bladder and rectal function. The positive neurological outcome in the patient in the present case underscores the significance of timely intervention. Whilst the synergistic impact of combining radiotherapy and immunotherapy in cancer treatment is widely emphasized, their influence on the spectrum and severity of toxicities remains underexplored. The present case, documenting LETM after treatment of tRCC with pembrolizumab, sheds light on a rare neurological adverse effect of ICIs. It underlines the need for prompt action in the effective management of immune-related adverse effects. Furthermore, the present case serves as a noteworthy contribution to the evolving understanding of the intricate dynamics between immune modulation and treatment-related complications in the context of innovative cancer therapies.