Paraneoplastic cerebellar degeneration is a rare complication of human cancer. This disorder is characterised by subacute onset of pancerebellar symptoms, often associated with dysfunction of other areas of the CNS. The onset of the degeneration may occur months before or after the detection of the primary cancer, or as a sign of its recurrence. It is usually associated with antineuronal antibodies directed against antigens coexpressed by the cells that undergo degeneration and by the associated tumour. Anti-Yo antibodies can be detected in serum and CSF of patients with paraneoplastic cerebellar degeneration with breast or gynaecological tumours. These antibodies show a coarse granular staining pattern of the cytoplasm of Purkinje cells, while the nucleus remains unstained.1 2 Patients with paraneoplastic cerebellar degeneration without anti-Yo antibodies may have other tumours, most commonly bronchial carcinoma or Hodgkin’s lymphoma, and may be positive for anti-Hu, anti-voltage gated calcium channels, or anti-Tr antibodies.1 Although the antibodies provide a diagnostic test for the associated tumours, it is generally thought that destruction of the Purkinje cells by autoreactive T cells is the major pathogenic mechanism, and previous reports suggest a lack of response to conventional immunosuppressive treatments. …