Brachial plexus neoplastic lesions assessed by conduction study of medial antebrachial cutaneous nerve.

Two cases of neoplastic involvement of the lower brachial plexus are reported. This condition was due to recurrence of lymphoma in one case and to axillary node spread of breast cancer in the other. The neuropathic origin and the location of the lesion in the lower brachial plexus between the T-1 root and the axilla was demonstrated by the presence of abnormalities on testing of the medial antebrachial cutaneous nerve in the symptomatic upper limb and comparing it to the healthy one. All other electrodiagnostic tests were normal. Such a finding suggests the need for imaging of the lower brachial plexus region by computed tomography or magnetic resonance imaging.