How would you approach a patient with DCIS (ER/PR/HER2 negative) with microinvasion in a SLN that is HER2 positive?  

Sentinel lymph node involvement in cases of DCIS without micro-invasion is rare and sentinel LN biopsy is generally not performed. Reported studies have shown SLN involvement rates of 2-3 %, and they are usually micro-invasion, as in this case. Once micro-invasion is detected in SLN, management shou...