Anti-Ri Paraneoplastic Neurologic Syndrome in a Patient With Untreated Breast Cancer

David X Li; Tyler Jarrett; Jessica Ma; Jonathan F Garcia

doi:10.7759/cureus.91743

Anti-Ri Paraneoplastic Neurologic Syndrome in a Patient With Untreated Breast Cancer

Cureus. 2025 Sep 6;17(9):e91743. doi: 10.7759/cureus.91743. eCollection 2025 Sep.

Authors

David X Li¹, Tyler Jarrett¹, Jessica Ma², Jonathan F Garcia²

Affiliations

¹ Internal Medicine, University of California Los Angeles, Los Angeles, USA.
² Hospital Medicine, University of California Los Angeles, Los Angeles, USA.

Abstract

Paraneoplastic syndromes (PNS) refer to a broad range of disorders that can impact any part of the nervous system and are frequently immune-mediated. Although classically associated with solid tumor malignancies, PNS remain a rare phenomenon. Anti-Ri-positive (antineuronal nuclear antibody type 2-positive) PNS is highly associated with breast cancer and results in a variety of clinical presentations, including cerebellar degeneration and opsoclonus-myoclonus syndrome. In this report, we describe a case of anti-Ri-positive PNS identified in a patient with a several-year history of untreated localized breast malignancy.

Keywords: anti-ri antibody; breast cancer; opsoclonus-myoclonus syndrome; paraneoplastic; paraneoplastic syndrome.

Publication types

Case Reports