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...

Need to find the primary invasive component. Breast MRI. Biopsy of any abnormal skin lesions. Possible mastectomy after MDTB discussion to ensure the presumed occult primary is appropriately addressed.Then RT and adjuvant systemic based on final path.