Paraneoplastic cerebellar ataxia associated with anti-hu antibodies and benign ganglioneuroma

We describe a case of cerebellar ataxia associated with anti-Hu antibodies and benign ganglioneuroma. A 28-year-old woman developed progressive ataxia with hyporeflexia at the age of 19. Brain MRI showed progressive cerebellar atrophy. Neurophysiological studies, screening of immune-mediated ataxias, oncological markers, vitamin E and genetic tests for spinocerebellar ataxia types 1,2,3, Friedreich ataxia and POLG1 were negative. Anti-Hu antibodies were positive in Western blot and indirect immunofluores- cence (1:640). Total-body computed tomography revealed a mediastinum mass; the histological diag- nosis was maturing ganglioneuroma. Immunohisto- chemistry showed a mild reaction between the tumor and the patient’s serum, and no reaction between the tumor and control serum. After surgery, serum anti-Hu titer decreased, while ataxic symptoms initial- ly worsened and then stabilized. Ganglioneuroma is a benign tumor, usually derived from the maturation of a neuroblastoma. The benign histology and the pres- ence of anti-Hu antibodies could be related to the positive oncological prognosis and to the slow clini- cal course mimicking a degenerative ataxia.