Lower extremity predominant stiff-person syndrome and limbic encephalitis with amphiphysin antibodies in breast cancer.

A 54-year-old woman presented with several weeks of psychiatric symptoms, partial-onset seizures, and painful spasms of the lower extremities. On examination, she exhibited severe stiffness and intermittent extensor spasms of the lower extremities. Magnetic resonance imaging of the brain showed T2 hyperintensity in the left temporal lobe with enhancement after gadolinium administration on T1-weighted images. Amphiphysin antibodies were present in the serum. Radiographic screening for malignancy disclosed a metastatic breast cancer. The case is a unique example of amphiphysin autoimmunity, illustrating the possibility of paraneoplastic stiff-person syndrome and limbic encephalitis coexisting in a patient with a "classical" presentation of stiff-person syndrome confined to the lower extremities.