Extradural malignancy simulating brachial neuritis

A 57 year old man is described who presented with symptoms and signs suggestive of brachial neuritis. Sparing of the serratus anterior both clinically and on electromyography suggested that the lesion was in the brachial plexus, thus supporting the diagnosis. Subsequent investigation showed an extradural tumour at C5-C6 level. Sparing of serratus anterior does not definitively localize the pathology as distal to the nerve roots.