Pearls & Oy-sters: Gait Instability, Jaw Dystonia, and Horizontal Diplopia in a Woman With Anti-Ri Antibodies and Breast Cancer

Abstract

A 40-year-old woman was admitted for six months of progressive gait disturbance, lower limb-predominant weakness, stiffness, falls, jaw dystonia, horizontal diplopia, and weight loss. Neurological examination revealed horizontal gaze paresis, limited jaw opening with palpable masseter hypertrophy, and spastic paraparesis with sustained clonus and upgoing plantar responses. MRI revealed T2-hyperintense signal abnormalities in dorsal pons, medulla and upper cervical cord central grey matter extending to C3, without gadolinium enhancement. Cerebrospinal fluid (CSF) showed mildly elevated protein and immunoglobulin (IgG) index with CSF-specific oligoclonal bands. Neural autoantibody testing was positive for anti-Ri in CSF and serum by mouse brain indirect immunofluorescence and immunoblot. Testing for aquaporin 4 (AQP4)-IgG and myelin oligodendrocyte glycoprotein (MOG)-IgG by cell-based assay were negative. The patient received methylprednisolone 1 gram for 5 days and intravenous immunoglobulin 2 grams/kilogram over 2 days with prednisone taper, and botulinum toxin injections for jaw dystonia. PET-CT revealed an enlarged left axillary lymph node with high FDG uptake. Left axillary lymph node biopsy confirmed high-grade, locally invasive breast adenocarcinoma. Neurologic stabilization was documented at two-week follow-up after hospital discharge before modified radical mastectomy. Our case demonstrates a clinical triad highly suggestive of anti-Ri-associated paraneoplastic neurologic syndrome (Ri-PNS): gait instability, jaw dystonia, and horizontal gaze paresis. The more slowly progressive course and poor response to immunotherapy help distinguish it from AQP4-IgG seropositive neuromyelitis optica spectrum disorder (NMOSD) and MOG-IgG associated disease that share similar radiographic features. Early diagnosis, prompt immunotherapy and cancer treatment are paramount for disease stabilization.

Gait instability, ophthalmoplegia, and chorea with orofacial dyskinesia in a man with anti-Ri antibodies: a case report

“…In the review by O’Toole, a favorable response to chemotherapy and immunotherapy was obtained in one of the patients, with regard to the patient’s chorea, but the patient in the case reported by Martinková and our patient did not show any improvement in their chorea with treatment. Furthermore, jaw dystonia is a common involuntary movement of the face in anti-Ri PNS patients ( 10 ). Orofacial dyskinesia, including grimacing, forceful jaw opening and closing, and masticatory-like movements, is often observed in patients with paraneoplastic chorea with positivity for anti-CRMP5/CV2, anti-Hu and anti-NMDAR antibodies ( 5 ) but has also been reported in patients with anti-LGI 1 ( 11 ) or anti-voltage-gated potassium channel complex antibodies ( 12 ).…”