Abstract
Accessory breast tissue has an incidence of 0.3–6% and primary cancer arising in it is even rarer 0.2–0.6%. It may have aggressive course with tendency for early metastasis. Due to its rarity, variety of differentials, and lack of clinical awareness, treatment is usually delayed. We present here an interesting case of a 65-year-old lady with a 8 × 7-cm hard lump in right axillary region for 3 years with fungation for 3 months and with no concomitant breast lesion or axillary lymphadenopathy. Biopsy revealed invasive ductal carcinoma with no systemic metastasis. Management of accessory breast cancer follows same guidelines with primary treatment being wide excision and lymphadenectomy. Adjuvant therapies include radiotherapy and hormonal therapy.
Keywords: Breast cancer, Axillary breast, Management
Ectopic accessory breast tissue results due to persistence of mammary ridge, and when it is present outside the confines of breast tissue but in same region, it is known as accessory breast tissue. Accessory breast tissue behaves similar to eutopic breast with regard to development, physiology, and pathology. It may remain undetected until it becomes apparent during puberty or pregnancy or is pathologically involved. The incidence of primary accessory breast cancer is rare around 0.2–0.6% of which 70–80% arises in the axilla [1]. The most common is not otherwise specified carcinomas (72%), others being lobular, medullary carcinomas, and phyllodes.
A 65-year-postmenopausal lady presented with a 8 × 7-cm lump in right axilla which was non-tender, mobile, hard, not fixed to the underlying structures. The overlying skin had an ulcer 6 × 4 cm, fixed to the underlying mass with everted margins (Fig. 1). No lump was palpable in the ipsilateral and contralateral breast and axilla with no palpable lymph nodes. Core needle biopsy revealed invasive ductal carcinoma, estrogen receptor (ER) and progesterone receptor (PR) positive, and HER2/neu negative. A chest X-ray, ultrasound of the abdomen and pelvis, and bone scan revealed no systemic metastases. Bilateral mammogram and ultrasound of the breasts revealed no abnormality. The patient is undergoing neoadjuvant taxane-based chemotherapy and is planned therafter for surgery.
Fig. 1.
Clinical photograph of the patient
There can be numerous differential diagnosis of a de novo axillary mass including skin appendage lesions, infections, hematoma, lymph nodes, and accessory breast tissue lesions such as in the present case, metastatic deposits, and intramuscular neoplasms. The differential diagnosis of a malignant mass includes cancer of mainly primary breast origin, either from the tail of Spence or from aberrant breast tissue in the axilla, and secondary metastatic carcinoma of axillary lymph nodes. The diagnosis of primary accessory breast cancer should fulfill the following criteria: absence of metastasis, no continuity with normal breast, presence of normal breast tissue around cancer, and absence of sudoriparous cancer in axilla [2]. Prognosis is same as normal mammary tissue carcinoma [3]. The management of accessory breast cancer follows the same guidelines as orthotopic breast carcinoma.
Surgical treatment comprises wide excision of the tumor with lymphadenectomy. This may be preceded or followed by chemotherapy. The other adjuvant modalities include radiation and hormonal therapy, if applicable. There exists some controversy with regard to mastectomy of ipsilateral breast. Although some have advised a modified/radical mastectomy in lymph node-positive disease, Evans and Guyton [4] and others have suggested that mastectomy has no survival advantage over wide local excision combined with axillary dissection or radiation. However, radiation of the normal ipsilateral anatomic breast is not recommended [1].
It is difficult to assess the prognosis of accessory breast cancer due to late presentation and lack of follow-up data. Most of the patients have advanced stage, nodal metastases, or large unresectable tumor at diagnosis. Four years post-treatment survival was found to be 9.4% [4].
Primary malignancy of accessory breast tissue is a rare entity. It may have aggressive course with tendency for early metastasis and invasion. Treatment includes a combination of surgery, chemotherapy, radiation, and endocrine therapy which should be individualized on a case to case basis.
Declarations
Conflict of Interest
The authors declare no competing interests.
Footnotes
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References
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