Morphological and immunohistochemical characterization of paraneoplastic cerebellar degeneration associated with Yo antibodies

Immunohistochemical studies of paraneoplastic cerebellar degeneration (PCD) are rare, and the findings vary.We performed morphological and immunohistochemical characterization of the brain, medulla and tumour of two patients with PCD, Yo antibodies and ovarian adenocarcinoma.The cerebellum of both patients had extensive loss of Purkinje cells. Microglia activation and T cells were found in the cerebellum, but B cells or deposits of IgG or complement were not detected. Microglia activation was also present in the brain stem and medulla. T cells were found in the ovarian adenocarcinoma.PCD is characterized by loss of Purkinje cells and microglia activation, and the presence of T cells indicates cellular immune reactions in PCD and in ovarian cancer.