Anti-Ri antibody opsoclonus-myoclonus syndrome and breast cancer: a case report and a review of the literature.

Opsoclonus-myoclonus is a rare neurological paraneoplastic syndrome associated with breast cancer and the presence of anti-Ri antibody. We presented a case of a 79-year-old woman with this syndrome and a small invasive ductal carcinoma [pT1aN0(sn)M0], whose symptoms improved 3 months following her simple mastectomy without any adjuvant therapy. Based on the 15 previously reported cases in the literature, there is no uniform treatment option available, and the response to such treatments is mixed.