Abstract P3-01-17: A technique for preoperative axillary lymph node tattooing in patients with breast cancer
Authors: Wapnir IL , Downey JR , Lipson JA , Ikeda DM 
Published: May 2016

Abstract
Purpose: To describe the ultrasound technique for tattooing axillary lymph nodes (ALNs) after lymph node (LN) biopsy in patients with breast cancer.
Background: Preoperative evaluation of metastatic disease within ALNs in patients with newly diagnosed breast cancer has significant prognostic value and is quickly becoming routine, particularly in the neoadjuvant setting. A recent study showed tattooed LNs are visible intraoperatively and on histological evaluation months following the tattooing procedure. These results suggest that LN tattooing can obviate the need for additional localization procedures during axillary staging, such as wire localization. Given the increasing use of preoperative ALN biopsy, a robust technique to insure proper LN tattoo marking is proposed.
Methods and Technique: Tattooing was performed under real-time US guidance using a 5-cm long 21-gauge hypodermic needle attached to a 1 mL tuberculin syringe containing 1 mL carbon suspension tattoo ink (SPOT™, GI-supply Inc).
Imaging was performed with the patient in a supine oblique position with the patient's arm over their head. The anatomically anterior and lateral aspects of the node and perinodal fat were marked with ink. The only regions of the LN not targeted for ink tattooing were the hilum and the posterior cortex and perinodal fat. At least 0.5 mL of ink was used.
Results: Optimal technique for intraoperative visualization was determined to be tattooing the anatomically anterior and lateral aspects of the LN cortex and the adjacent perinodal fat using at least 0.5mL of ink.
Tattooed LNs which had undergone biopsy and tattooing months prior to surgery were visible intraoperatively and on histological evaluation.
Factors contributing to less optimal visualization of the tattooed lymph node included: using less than 0.5mL of ink, tattooing only the superficial cortex and not the perinodal fat, and tattooing a portion of the LN that was not visible with the patient in the operative position.
Discussion: The most easily accessed portion of the LN during the US procedure may not be the portion of the LN most easily seen intraoperatively. Locating and tattooing the anatomically anterior and lateral aspects of the LN, regardless of the patient position and orientation of the ultrasound probe, is the primary challenge. Doing so will maximize the likelihood that the tattoo ink will be visible by the surgeon when the patient is in a supine position with the arm abducted 90 degrees using an axillary incision.
Tattooing using less than 0.5 mL resulted in suboptimal visualization. Using a larger volume of ink may be judged necessary for larger LNs, very fatty axillae, and for deeply seated nodes.
Other reports in the medical literature suggest cutaneous tattooing can result in ink within ALNs. In patients with ipsilateral cutaneous tattoos, an alternative method of marking any biopsied LNs should be considered to avoid false positives associated with prior migration of the cutaneous tattoo ink to the LN.
Tattooing of ALNs under ultrasound guidance is a straightforward technique which can be performed at the time of initial biopsy and obviates the need for future preoperative wire localization of the LN.
Citation Format: Wapnir IL, Downey JR, Lipson JA, Ikeda DM. A technique for preoperative axillary lymph node tattooing in patients with breast cancer. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-01-17.