Longstanding Breast Mass

CLINICAL HISTORY

A 34-year-old Hispanic woman presented to her primary-care physician with a palpable left breast mass in June of 2009. She first noticed the mass 15 years prior, but never sought medical care. She has no significant past medical or surgical history. There is no history of cancer in her immediate family. Menarche occurred at age 14. She gave birth to the first of two children at the age of 22. She denies having ever taken birth control pills, hormone replacement therapy, or fertility drugs.

FINDINGS

The palpable mass corresponds on the mammogram to be a sharply marginated, lobulated soft tissue mass, 4.2 x 4.2 x 3.7 cm. This is in the OUQ of the left breast. There are no associated microcalcifications. Sonographic evaluation demonstrates a sharply defined complex solid mass with a few cystic areas. There are no areas of acoustic shadowing, but there may be some questionable areas of acoustical enhancement. Color flow imaging demonstrates minimal vasculature in the mass, but it is not hypervascular.

DISCUSSION

The patient subsequently underwent a left breast lumpectomy and sentinel node biopsy in July of 2009. The pathology report indicated that the mass was an intermediate grade adenoid cystic carcinoma and the two excised lymph nodes were negative for metastatic disease (staged T2, N0). Adenoid cystic carcinoma (ACC) of the breast is a very rare form of breast cancer, accounting for approximately 0.1 percent of all breast cancer cases¹.

Most women are postmenopausal at presentation. ACC has an excellent prognosis with few reports of metastatic disease. It is a slow growing lesion with a low recurrence rate. Long term survival rates are high. Metastases are primarily found in the lungs, but can also be seen in the liver, brain and kidneys¹.

ACC of the breast is histologically akin to ACC of the salivary glands². More than half of these tumors will be hormone receptor positive (ER+/PR-, ER-/PR+ or ER+/PR+). Although it is unclear what cells are responsible for these lesions, ductal, myoepithelial, and stem cells have all been theorized as possible candidates². Of the small subset of patients with distant metastatic disease, the majority have negative lymph nodes, which makes axillary node dissection unnecessary. Like other more common forms of breast cancer, treatment consists of lumpectomy plus adjuvant radiation therapy or mastectomy alone in order to prevent local recurrence³. Adjuvant chemotherapy is added to the regimen if there is metastatic disease.

1 Leeming R, Jenkins M, Mendelsohn G. Adenoid cystic carcinoma of the breast.Archives of Surgery.1992; 127:233-235.

2 Pia-Foschini M, Reis-Filho JS, Eusebi V, Lakhani SR. Salivary gland-like tumours of the breast: Surgical and molecular pathology. Journal of Clinical Pathology.2003; 56: 497-506.

3 Arpino G, Clark GM, Mohsin S, Bardou VJ, Elledge RM. Adenoid cystic carcinoma of the breast: Molecular markers, treatment and clinical outcome.Cancer. 2002; 94: 2119-2127.

Dr. Shively is a resident at Penn State Milton S. Hershey Medical Center in Hershey, Penn., and Drs. Pyatt and Lampton are affiliated with Summit Health System in Chambersburg, Penn.