A case of adenoid cystic carcinoma of the breast.

A 57-year-old woman was referred to our institution 4 months after she noticed a palpable, painless mass in her left breast. Physical examination revealed a mobile and elastic mass. An axillary or subclavicular lymph node was not palpable. Mammography revealed a lobulated mass with a partially ill-defined border. Ultrasonography depicted a 2.5 × 1.5 cm irregularly shaped mass with heterogeneous internal echo and posterior acoustic enhancement. The border of the mass was poorly defined at the anterior and lateral aspects of the mass. Results of ultrasonography-guided fine-needle aspiration cytology were strongly suggestive of a malignant tumor. Thus, the patient underwent breast-conserving surgery with axillary lymph node dissection. The gross resected specimen revealed a gray-to-white and well-demarcated solid tumor measuring 3 × 2 × 2.5 cm, with an irregular border and heterogeneous internal structure. Histological examination showed the characteristic patterns of adenoid cystic carcinoma of the breast. Immunohistochemical studies for both estrogen receptors (ER) and progesterone receptors (PgR) were negative. The patient remains well and has no clinical recurrence of the disease after 5 years of follow-up without radiotherapy or adjuvant therapy.