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Supernumerary Axillary Breast Cancer

To the Editor: This case report presents an opportunity to discuss the treatment of supernumerary breast cancer which is seldom mentioned in the surgical literature, and suggests some novel therapeutic considerations. Supernumerary breast may present characteristics analogous to normal breast tissue in terms of function and, more importantly, pathologic degeneration although treatment option can differ (1). We describe a case of supernumerary axillary breast cancer who needed a reconstruction with latissimus dorsi flap. Accessory breast tissue has a very rare incidence in population with incidence rates of 1–2%. Furthermore, having an accessory breast with concurrent breast cancer is extremely rare with only few articles published in the literature (2). The exact incidence of breast cancer in supernumerary breast tissue is unknown but estimates range in 0.3–0.6%. Both the rarity of the pathology and its sometimes unusual clinical presentation of lumps without nippleareola-complex makes diagnosis very challenging, and the first contact physician is not often including supernumerary breast cancer as part of the differential diagnosis (3). The approach to supernumerary breast cancer should follow the same sequence of clinical examination, mammography, sonogram, and fine-needle aspiration cytology or core needle biopsy as performed usually for anatomic breast cancer. Standard mammograms do not usually show axillary supernumerary breast because of its high location, but with special positioning of the patient, however, ectopic breasts are sometimes imaged. Therapeutic options are also based on standard breast cancer treatment of anatomic breast. Surgical removal is the mainstay of treatment with either mastectomy or wide local excision for a conservative approach, and axillary staging with sentinel lymph node biopsy according to actual evidences (4–7). Some authors recommended radical mastectomy of the ipsilateral breast if the regional lymph nodes are diagnosed with carcinoma (8). However, Evans and Guyton (9) concluded that ipsilateral mastectomy in addition to axillary lymph node dissection was not superior to local excision with node dissection. Thus, it has been proposed that the surgical procedure of choice for ectopic breast carcinoma is wide local excision of the tumor including the skin and the surrounding supernumerary breast tissue, sentinel lymph node sampling and axillary clearance if appropriate (1). Mastectomy of the ipsilateral normal breast gland is not indicated if clinical examination, mammography, and ultrasound of the anatomic breast show no signs of disease, and should only be considered in cases where the differential diagnosis is confusing (2). In all cases careful follow-up is necessary to exclude any late manifestation of an occult primary neoplasm of the breast. Postoperative adjuvant therapy should be based on clinical stage, tumor biology, and patients characteristics. Radiotherapy, chemotherapy regimens, antibodies, and endocrine therapy are usually based on standard treatment for anatomic breast cancer. The exact prognosis of such cases is not known due to the limited data on follow-up and sample size. We discuss a case of a 42-year-old female with cancer arising in supernumerary breast. The patient was seen in our Institution because of complaint regarding a mass located in her right axilla. At her clinical examination a 2 cm hard mass with irregular borders in the right supernumerary breast was detected (Fig. 1). Imaging with mammography and high definition ultrasound revealed a suspicious 1.5 cm hypoechoic mass in the right supernumerary breast, with increased vascularity. The rest of the glandular breast tissue appeared to be normal. Fine-needle aspiration cytology of the tumor was performed, resulting in a C5 category lesion. An interdisciplinary team approach recommended wide local excision of the mass including the involved supernumerary breast, Address correspondence and reprint requests to Antonio Toesca, Division of Breast Surgery, European Institute of Oncology, Via Ripamonti 435, 20141 Milano, Italy, or e-mail: antonio.toesca@ieo.it