Anti-Yo antibody-associated Autoimmune Encephalitis due to Breast Adenocarcinoma in a male patient.

Paraneoplastic neurological syndromes occur due to immune-mediated neuronal dysfunction secondary to systemic malignancy, and symptoms can usually be seen before malignancy. There are many subtypes that depend on the antibodies present or the proteins they target. Accurate epidemiological data are lacking as it is difficult to diagnose. We would like to present a case of anti-Yo antibody-associated encephalitis due to breast cancer in a 47-year-old male patient. When we searched the literature, we did not find a case of anti-Yo-associated autoimmune encephalitis due to breast adenocarcinoma in a male patient. For this reason, we find it worth presenting our case.