[Chemotherapy treatment for anti-Hu paraneoplastic syndrome without active malignancy]. / Traitement par chimiothérapie d'un syndrome neurologique paranéoplasique anti-Hu sans cancer actif associé

INTRODUCTION: Anti-Hu associated paraneoplastic neurological syndromes are rare and characterized by poor prognosis. The research and treatment of a related cancer, a small-cell lung cancer most of the time, remains the best therapeutic strategy. CASE REPORT: We describe the clinical course of a paraneoplastic subacute sensory neuronopathy associated with anti-Hu antibodies in a male smoker treated by an early chemotherapy active against a small-cell lung cancer although no tumor could be found at repeated evaluations. In spite of this treatment, the neurological state deteriorated with the appearance of a cerebellar degeneration, and limbic encephalitis which resulted in a loss of autonomy. A small-cell lung cancer was found and treated 65 months after the onset of the neurological symptoms. The treatment of the underlying malignancy, when it can be found, is still considered as the optimal treatment for paraneoplastic neurological syndromes. Although no tumor could be found, we treated our patient with an empirical chemotherapy active against the most frequent malignancy associated to anti-Hu syndrome in a smoker man, without any improvement. CONCLUSION: Active and repeated research for a cancer related to an anti-Hu neurological syndrome and its treatment are undispensable. For our patient without any identified cancer empirical chemotherapy treatment was unable to stop neurological worsening. When no tumor can be identified by conventional imaging techniques, an early FDG-PET scan should be considered and then repeated if normal.