Anti‐ Yo ‐associated paraneoplastic cerebellar degeneration in a man with adenocarcinoma of unknown origin

Anti-Yo-associated paraneoplastic cerebellar degeneration (PCD) is almost invariably associated with breast or gynecologic tumors. 1 In this syndrome, anti-Yo autoantibodies react with 34- and 62-kd antigens simultaneously expressed by tumor and Purkinje cells. 2 Using immunohistochemistry, similar staining (although not always identical) antibodies have been found and named by others PCA-1 and type I antineuronal antibodies. 3 Only one male patient, in whom no tumor was found, has been reported with anti-Yo-associated PCD. 4 We report another man with anti-Yo-associated PCD in the context of a carcinoma of unknown origin. A nonenzymatic method to unmask antigens in paraffin-embedded tissue helped to demonstrate that the tumor expressed Yo antigens. A 68-year-old right-handed man with a medical history of heavy tobacco and alcohol use presented to the neurology clinic with a 2-month history of progressively unsteady gait and frequent falls. He denied heavy alcohol use over this period. On physical examination he had gynecomastia and normal male genitalia except for an undescended testis. There was severe bilateral dysmetria involving only the legs, without weakness or sensory loss. A repeat examination 1 month later demonstrated progression of symptoms. It also showed dysarthria with scanning speech, multidirectional gaze-evoked nystagmus, …