Paraneoplastic painful ulnar neuropathy.

A 58-year-old woman developed painful, bilateral ulnar neuropathy in conjunction with small cell lung carcinoma and high serum titer of anti-Hu antibody. An incidental stage I plasma cell dyscrasia, with immunoglobulin G kappa monoclonal protein, was also present. Electropysiological assessment excluded a generalized neuropathy, and nerve biopsy showed marked loss of myelinated and small unmyelinated fibers, without inflammatory changes or amyloid deposition. High titers of circulating anti-Hu antibody can be associated with symptoms resembling a paraneoplastic mononeuropathy.