Most frequent location of the sentinel lymph nodes

SummaryBackgroundInappropriate skin incisions can make sentinel lymph node dissection difficult. A knowledge of the most common locations of the hotspot in the axilla helps in planning the incision. This information also helps to locate the lymph node preoperatively by ultrasound. The aim of this prospective study was to determine the most common location of the sentinel lymph node in the axilla.MethodsFrom January 2006 to December 2010, 974 consecutive patients who underwent sentinel lymph node dissection guided by 99mTc–sulfur colloid were included and the position of the hotspot in the axilla was recorded prospectively. The location of the hottest spot on the skin of the axilla was categorized into seven areas divided by five landmarks.ResultsIn 98.4% of our patients, the hotspot detected on the axilla skin before sentinel lymph node dissection was located in the area demarcated by the four landmarks of the hairline, a line tangential to and 2 cm below the center of the hairline, the lateral border of the pectoralis major muscle, and the mid-axillary line.ConclusionThe area between these four landmarks is the most frequent location of the sentinel lymph node identified using the radioisotope method. We suggest that this area should be carefully evaluated preoperatively by ultrasound for appropriate surgical planning. A skin incision in this area is also recommended when sentinel lymph node dissection is guided by blue dye.