Diagnostic value of MR imaging in the Lewis-Sumner syndrome: a case series.

Lewis-Sumner syndrome (LSS) is considered a variant of chronic inflammatory demyelinating polyneuropathy (CIDP), which is more frequently described with exclusive upper limb involvement. The diagnosis of LSS is clinical and electrophysiological. However, these are not always obvious and in view of its rarity, the diagnosis may be missed and patients denied effective immunomodulatory therapy. We herein describe the magnetic resonance imaging (MRI) findings in a series of five consecutive patients with a clinical diagnosis of LSS, using T2 STIR (Short Tau Inversion recovery) images without contrast. We demonstrated hyperintensity with or without hypertrophy of cervical roots and/or brachial plexus on the affected side and/or controlaterally which aided diagnostic confirmation. This helped therapeutic decision making regarding immunotherapy in all cases. MR imaging of the cervical spine/brachial plexus with T2 STIR may be helpful in suspected cases of LSS as it represents a very useful additional diagnostic tool.