Paraneoplastic subacute sensory neuropathy with triple positive antineuronal antibodies associated with small-cell lung cancer.

A 67-year-old woman with a history of smoking and cardiovascular risk factors was admitted to the emergency room for uncontrolled diabetes, loss of appetite, nausea, significant weight loss and asthenia. The initial investigation, including cerebral and gastrointestinal explorations, were normal. One month later, she started presenting severe asymmetric proprioceptive ataxia of the lower extremities. She also reported paresthesia and neuropathic pain in both feet and ankles. A positron emission tomography (PET)-scanner showed a hypermetabolic nodule in the right lung. The neurological symptoms were attributed to paraneoplastic sensory and dysautonomic neuropathy, even though the bronchoscopic biopsies came back negative at first. Anti-Hu, anti-CV2/CRMP5 and anti-SOX1 antibodies were documented. Due to the severity and rapid progression of symptoms (from the lower to the upper limbs), corticosteroids, intravenous immunoglobulins and immunosuppressants were introduced prior to biopsies revealing a small-cell lung cancer. Despite these treatments and antineoplastic chemotherapy, her status deteriorated rapidly.