Paraneoplastic cerebellar degeneration (PCD) is a heterogeneous group of disorders characterised by the subacute onset of a cerebellar syndrome in patients with cancer. Although PCD may occur in patients with a variety of cancers with or without autoantibodies, it is most commonly associated with ovarian or breast tumours in women seropositive for anti-Yo antibodies. Anti-Yo antibodies bind to protein antigens of 34 and 62 kDa, respectively, found exclusively in the cytoplasm of Purkinje cells. Morphological studies have revealed loss of Purkinje cells accompanied by relatively few or absent inflammatory changes.¹ We present a case of a man with a subacute cerebellar syndrome in whom further diagnostic workup disclosed prostatic adenocarcinoma (PA) and anti-Yo antibodies. Furthermore, the PA showed expression of Yo antigen. Therefore, this case represents simultaneously the first case of PCD associated with PA as well as the fifth case of anti-Yo positive PCD in a male patient.

Case report

A 79-year-old, previously healthy man presented with a 6 month history of disequilibrium that had aggravated in the past 10 days. Neurological examination revealed a cerebellar syndrome with unsteadiness of stance and gait, scanning dysarthria, nystagmus and saccadic dysmetria, and dysdiadochokinesis. Both MRI and CT of the brain were unremarkable. Apart from oligoclonal bands, examination of CSF was normal. Routine laboratory analysis revealed elevated serum levels of prostate specific antigen (174 μg/l; normal <4.2 μg/l). In core biopsies of the prostatic gland, the diagnosis of adenocarcinoma was made. Further laboratory studies detected anti-Yo-antibodies both in the patient’s serum and in CSF (fig 1A) by western blot analysis using recombinant Yo …