Paraneoplastic limbic encephalitis cured with nephron-sparing surgery in a patient with clear cell renal cell carcinoma: a case report

Paraneoplastic limbic encephalitis (PLE) in association with clear cell renal cell carcinoma has never been reported in China. We herein describe a 54-year-old man with a 1-week history of headache and a 3-day history of psychiatric symptoms. Slight nuchal rigidity was found by physical examination. Imaging studies of the head were normal. Blood and cerebrospinal fluid antibody testing were both positive for N-methyl-D-aspartic acid antibodies. Subsequent contrast-enhanced computed tomography revealed a 5.2- × 4.2-cm left kidney mass with intense enhancement. Emergent laparoscopic nephron-sparing surgery was successfully performed. Immunohistochemistry revealed clear cell renal cell carcinoma. The patient’s status improved after the surgery, and he was discharged after 1 month of hospitalization. At the 6-month follow-up, magnetic resonance imaging showed no recurrence, and the patient was living independently. This case indicates the potential effect of nephron-sparing surgery in the treatment of PLE. Tumor screening should be performed early in patients with suspected PLE. Early surgical resection of the primary tumor can improve patients’ prognosis.