Neuroblastoma-associated paraneoplastic syndrome with anti-Hu antineuronal antibodies presenting at the time of recurrence.

A 27-month-old girl presented with chest pain. Further evaluation confirmed posterior mediastinal neuroblastoma with bone marrow infiltration, which was treated with a combination of chemotherapy and surgery. Four months after completing treatment, she presented with myoclonus and weakness of her right arm. The myoclonus eventually subsided but her right arm weakness progressed to a right hemiplegia. High titers of antineuronal nuclear antibodies identified as anti-Hu were found in both serum and cerebrospinal fluid. One month later she presented with a relapse of her original tumor, from which she died. Identification of anti-Hu antineuronal nuclear antibodies in this neuroblastoma-associated paraneoplastic syndrome supports the hypothesis that the syndrome is due to autoimmune disease.