Discordant lymphatic drainage patterns revealed by serial lymphoscintigraphy in cutaneous head and neck malignancies.

BACKGROUND We analyzed the variability and accuracy of sentinel lymph node (SLN) identification by lymphoscintigraphy performed preoperatively and repeated on the day of operation in patients with melanoma or Merkel cell cancer. METHODS Twenty-five prospectively studied patients had lymphoscintigraphy prior to and on the day of operation. Discordance between lymphoscintograms was defined as change in location of SLN or failure to identify a SLN by one of the studies. RESULTS In 22 of 24 assessable cases (92%), SLNs were excised. Preoperative lymphoscintigraphy was correct in 19 of 22 (86%) cases. Day of operation lymphoscintigraphy was correct in 20 of 22 (91%) cases. SLN location was as classically described in 24 of 25 (96%) cases. Discordance between lymphoscintigraphy studies was 32% (8/25 patients). Half with discordant migration (8%) yielded metastases in basins not identified by day of operation lymphoscintigraphy but demonstrated by preoperative lymphoscintigraphy. CONCLUSIONS Head and neck lymphatic drainage patterns not only vary between patients but also can vary with time for a single patient.