Lactating breast abscess: a rare presentation of adenosquamous breast carcinoma

We report the case of a 33-year-old lactating woman who presented with a 10-cm breast abscess. Biopsy of the abscess wall revealed a poorly differentiated invasive ductal carcinoma. The patient had no family history of breast cancer or other risk factors for breast cancer. The disease was considered to be a large noninflammatory invasive breast cancer, for which the patient received neoadjuvant chemotherapy, breast-conserving surgery using axillary dissection (the patient did not consent to a mastectomy), and postoperative radiotherapy. Final histologic examination revealed a 4-cm, triple negative, high-grade adenosquamous carcinoma. At follow-up four years after surgery, the patient was doing well with no signs of recurrence. Adenosquamous carcinoma is an extremely rare disease that mainly presents in low-grade forms. High-grade forms are aggressive and frequently present with axillary involvement. To the best of our knowledge, there has been no report of adenosquamous carcinoma presenting as a breast abscess in the literature. The case we report highlights that, although rare, cancer should be considered in lactating breast abscesses.