[Lesion of the intercostobrachial nerve]

After surgery in the area of the armpit, and particularly after axillary lymphonodectomy during mastectomy, severe pain and paraesthesia can occur in the region of the medial and posterior side of the proximal upper arm. It is shown by means of four case reports that this discomfort can be caused by a lesion in the intercostobrachial nerve. The differential diagnosis must consider injury to the brachial plexus or a local metastasis.