INTRODUCTION: Adenoid cystic carcinoma of the breast (ACCB) is a rare malignancy with favorable prognosis: axillary lymph node involvement, distant metastases, and death due to disease are uncommon. ACCB may recur locally many years after primary surgical excision and may be substantially higher if primary procedure is lumpectomy rather than mastectomy. METHODS: Pathology database searched to identify patients diagnosed with ACCB between 1988 and 2007 at Hamilton Health Sciences Centre, Hamilton, Ontario, Canada.Two pathologists independently reviewed histology to confirm diagnosis of ACCB, and documented surgical procedure, tumor size, tumor grade, surgical margin, and lymph node status. Immunohistochemistry was performed on representative blocks and independently reviewed by 2 pathologists. Clinical and radiologic data were retrospectively reviewed. RESULTS: Fifteen cases of ACCB were identified and pathology slides were available for 12. The median age was 62 years. Seven patients presented with a palpable mass and breast pain was described in 3. Positive surgical margins were identified in 5 patients (42%). Only 3 patients had postoperative radiation therapy. CONCLUSIONS: Our series shows frequent resection margin involvement in ACCB. Neither clinical nor mammographic examination consistently delineated full tumor extent preoperatively. Future use of magnetic resonance imaging in preoperative assessment may prevent high positive margin rate when lumpectomy is planned. Histologic assessment of tumor extent may be difficult, but immunohistochemistry may be helpful in this regard.
