Paraneoplastic Choreoathetosis in a Patient with Small Cell Lung Carcinoma and Anti-CRMP5/CV2: A Case Report

Introduction: The occurrence of more or less monosymptomatic paraneoplastic choreoathetosis associated with anti-CRMP5/CV2 antibodies is rare. Typically, such autoantibodies are associated with a more classical syndrome - paraneoplastic encephalomyelitis. Frequently, small cell lung carcinoma (SCLC) is the related neoplastic finding. Case Report: We present a 71-year-old woman who developed visual symptoms with papilledema and chorea. Anti-CRMP5/CV2 antibodies were a feature of both the serum and cerebrospinal fluid. Although SCLC was suspected already at the time of the initial examinations, no signs of primary or metastatic tumors were revealed on chest X-ray, MRI or whole-body PET scan. EEG and bronchoscopy were also unremarkable. However, 6 months after the onset, a repeated PET scan and subsequent bronchoscopic biopsy revealed SCLC. In spite of chemotherapy, the SCLC progressed, and the patient died 14 months after the onset of the symptoms. Conclusion: We report paraneoplastic choreoathetosis associated with anti-CRMP5/CV2 antibodies. Such published case histories are rare. Although expected, we did not find any reduced signal intensity at the basal ganglia on the T1-weighted or increased intensity on the T2-weighted MRI scans.