Anti-Ri-Associated Paraneoplastic Neurological Syndrome Revealing Breast Cancer: A Case Report.

Neurological paraneoplastic syndromes are a rare entity that affects patients with cancer. Anti-Ri antibodies affect the brain stem and produce a heterogeneous rapidly progressive subacute syndrome depending on the involvement of the different regions concerned. The most common clinical presentation is opsoclonus-myoclonus syndrome and paraneoplastic cerebellar degeneration. Here we report a case of a 60-year-old woman with a subacute static-kinetic cerebellar syndrome, cervical dystonia, and multiple cranial nerve palsies revealing a mammary adenocarcinoma. Anti-Ri antibodies were positive in her blood. Our observation underscored the importance of the identification of the tumor for early treatment management to avoid irreversible neurological manifestations.