Echchaoui and Daoud: Axillary Accessory Breast Tissue Mimicking Lipoma


Accessory breast (AB) also known as polymastia or supernumerary breasts is an ectopic breast tissue, it may develop due to an incomplete regression of the embryonic mammary ridge “milk line” which extends from the axilla to the groin [1, 2]. It is a rare congenital entity which occurs in 0.4-6% of women, the highest incidence occurs in the Japanese population [3, 4]. It is equally found in males and females [5]. AB was classified by Kajava in 1915 [6] as follows:

  • Class I consists of a complete breast with nipple, areola, and glandular tissue.

  • Class II consists of nipple and glandular tissue but no areola.

  • Class III consists of areola and glandular tissue but no nipple.

  • Class IV consists of glandular tissue only.

  • Class V consists of nipple and areola but no glandular tissue (pseudo mamma).

  • Class VI consists of a nipple only (polythelia).

  • Class VII consists of an areola only (polythelia areolaris).

  • Class VIII consists of only hair (polythelia pilosa).

AB may appear with or without nipples or areolae, they are mostly located in the axilla but such locations as the face, thighs, abdominal wall, perineum and vulva are also possible [7-9].

AB can undergo the same physiological and pathological changes that occur in a normal breast, such as response to hormonal influences, carcinoma and fibrocystic disease [10, 11].

The diagnostic is usually made by physical examination especially when it is bilateral with areola and nipple, but it can be confused with lipoma, lymphadenopathy, sebaceous cyst, vascular malformation, and malignancy [12]. Ultrasonography is an examination of choice and can show ectopic breast tissue in axilla. Fine-needle aspiration or excisional biopsy confirms the diagnosis [13].

Asymptomatic accessory breast require no treatment and should be monitored for detecting malignant change [14]. The treatment of choice is preventive resection which is generally recommended in case of functional symptoms and/or cosmetic discomfort [15]. Liposuction can be performed alone or in combination with a surgical excision [16, 17].

Case Presentation

We report a case of a 36-year-old women presented with a history of painless axillary swelling since birth. She noticed an increase in size and pain in the masse during her menstrual cycle. Physical examination revealed a firm in consistency, 5x3cm, non-tender, freely mobile swelling with no nipple or areola distinguished (Figure 1). The diagnosis of axillary lipoma was clinically made.

Fig. 1.

Right-sided axillary accessory breast


Ultrasonography revealed ectopic breast tissue. It was accordingly classified as class IV type of Kajava ectopic breast tissue classification.

The swelling was excised under general anesthesia. Histopathology was conclusive of ectopic breast tissue with no evidence of malignancy.

The postoperative course was uneventful and the patient left the hospital on the 3th postoperative day. The mean follow-up duration was 9 months. No tumor recurrence occurred and no severe complications were reported. The patient was satisfied about functional and cosmetic result (Figure 2).

Fig. 2.

Postoperative view three months after surgical excision



This uncommon congenital condition can be mistaken for benign lesions like lipomas.

Malignant lesions can be originated from ectopic breasts tissue in axillae and warrants monitoring and preventive excision.

Source of support

Declared none.

Competing interests

The authors declare no competing interests.

Author’s contributions

All the authors have actively participated in the redaction, the revision of the manuscript and provided approval for this final revised version.



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Copyright (c) 2017 Abdelmoughit Echchaoui, Ghattas Daoud

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