Breast adenosquamous cell carcinoma presented in an intracystic form

Summary Intracystic carcinoma is not common seen in breast malignancy, here we showed a case of intracystic tumor presented in adenosquamoid differentiation. Negative in ER, PR, and HER2 makes treatment out of hormone and target therapy. After simple mastectomy with sentinel lymph node biopsy, we found isolated tumor cell over lymph node. Although AJCC takes ITCs as N0 category, the presence of ITCs is considered as a prognostic factor influencing both the overall and breast cancer-specific survival, thus we gave the patient with adjuvant chemotherapy as locally advanced breast cancer in the NCCN guideline.