[Anaphylactic shock due to "patent blue" used to search for the sentinel node]

Intraoperative search for the sentinel node using patent blue is considered a non risk procedure. We report the first case of anaphylactic shock and allergy. We emphasize the highly exceptional nature of this adverse effect previously observed in other disciplines using this coloring agent. In light of the favorable outcome in our patient and the importance of the method, this single accident would not be sufficient to contraindicate the continuing use of patent blue in ongoing research.