Atypical lymphatic mapping in sentinel lymph node detection in breast cancer.

Sentinel lymph node detection is applied widely for the management of breast cancer, and the external lymphoscintigraphy provides the surgeon with an accurate map of the lymphatic drainage. Although the most frequent drainage for breast cancer is toward the axillary nodes in 94%, various patterns have been described, especially in the internal mammary chain. In the literature, lymphatic drainage in breast cancer is usually limited to the trunk. We report an atypical case with drainage to an upper extremity.