Rare breast metastasis from adenoid cystic carcinoma of the submandibular gland.

Adenoid cystic carcinomas (ACCs) are rare malignant neoplasms of exocrine glands, most commonly found in salivary glands. This report describes a 67-year-old woman with metastatic ACC to the breast, only the third reported case of its kind. The salivary gland ACC was first diagnosed 5 years prior. Routine mammogram identified a Breast Imaging and Reporting Systems (BIRADS) 4 lesion. Core breast biopsy demonstrated findings consistent with metastatic ACC to the breast. The patient ultimately underwent local excision but suffered a recurrence of disease less than 2 months later despite chemotherapy. She passed away 15 months after excision due to complications associated with a small bowel obstruction and decompensated respiratory status from pulmonary metastases. While metastatic salivary ACC to the breast is rare, it is important to be able to distinguish metastatic salivary ACC to the breast from primary ACC of the breast as the treatment considerations for the two disease processes differ significantly.