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 Table of Contents  
Year : 2017  |  Volume : 20  |  Issue : 3  |  Page : 129-133

Clinico-pathologic spectrum of accessory axillary breast; case series and literature review

1 Department of Morbid Anatomy and Forensic Medicine, College of Health Sciences, Usmanu Danfodiyo University, Sokoto, Nigeria
2 Department of Pathology, Ahmadu Bello University Teaching Hospital, Zaria, Kaduna State, Nigeria

Date of Web Publication16-Jan-2018

Correspondence Address:
Dr. Usman Bello
Department of Morbid Anatomy and Forensic Medicine, College of Health Sciences, Usmanu Danfodiyo University, Sokoto
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/1118-8561.223167

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Accessory breast and the diseases affecting these aberrant breast tissues are relatively uncommon, and with variable prevalence among different populations. These are commonly located in the axilla, chest wall, and vulva. The most common disease in these tissues is carcinoma; however, other benign neoplastic and nonneoplastic lesions do occur. In this review, we present a clinicopathologic analysis of all the consecutive cases seen in a major referral teaching hospital over a period spanning 10 years (2006–2015).

Keywords: Accessory breast, axilla, carcinoma, fibrocystic change

How to cite this article:
Bello U, Omotara SM. Clinico-pathologic spectrum of accessory axillary breast; case series and literature review. Sahel Med J 2017;20:129-33

How to cite this URL:
Bello U, Omotara SM. Clinico-pathologic spectrum of accessory axillary breast; case series and literature review. Sahel Med J [serial online] 2017 [cited 2023 May 30];20:129-33. Available from: https://www.smjonline.org/text.asp?2017/20/3/129/223167

  Introduction Top

The occurrence of accessory breast in the general population is variable and depends on the gender, race, genetic disposition, and geographic location. In general, the prevalence rate ranges from 0.4% to 6%, and it is more common in females (5.19%) than in males (1.68%).[1] Supernumerary breast is the development of accessory nipple and/or areola complex with or without glandular breast tissues, whereas aberrant breast refers to ectopic breast tissue without a nipple or areola complex. Supernumerary mammary glands develop along the ectodermal ridges (the milk line) which extend from the axilla to the pubes and may occur as either unilateral or bilateral lesions in affected individuals. These glands either mature into mammary glands or remain as accessory nipples in 2–6% of women.[2] Furthermore, the accessory breast tissue responds to the hormonal influences of the menstrual cycle, pregnancy, and lactation just as the anatomically normal breast. Unusual sites of occurrence outside the milk line include knee, lateral thigh, buttock, face, ear, and neck.[3],[4],[5]

Diseases of the normally located breast tissue may also be seen in the ectopic breast tissue including lactational changes, infections, and neoplastic lesions.[6],[7],[8],[9],[10],[11] These accessory breast tissues have been missed clinically and diagnosed as neoplastic lesions which compromises treatment of affected persons. This is a histopathologic analysis and clinical correlations [Table 1] of ectopic axillary mammary glands over a ten year period.
Table 1: Clinico-Pathologic Characteristics of Cases of Axillary Accessory Breasts

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  Cases Reports Top

Case 1

A 40-year-old para 2 + 1 female who presented with a 5-year history of slowly enlarging left axillary swelling. The swelling was first noticed when she breastfed her first child. Swelling increased with subsequent pregnancy and lactation. There were no other palpable swellings in any part of her body. Her last childbirth was 16 months before presentation. The mass was clinically soft, mobile, painless and measured 4 cm × 3 cm × 3 cm in dimension. A clinical impression of lipoma was made and she had an excisional biopsy done. Histology revealed fibrocystic change of an accessory breast tissue.

Case 2

A 50-year-old para 3 petty trader. She presented with a 9-month history of progressive right axillary swelling, associated weight loss and low-grade fever. Her last childbirth was 15 years ago, and she is using both oral and injectable contraceptives. Her medical history was unremarkable though her elder sister died of breast cancer while her mother is well and alive. Clinical examination revealed a middle-aged fairly preserved woman with an axillary mass measuring 7 cm × 5 cm × 3 cm and no other palpable masses in the breasts or anywhere else. A diagnosis of metastatic cancer of unknown primary was made. Mammogram of both breasts was unremarkable. Incisional biopsy of the axillary mass sent for histopathological analysis revealed a diagnosis of invasive ductal carcinoma [Figure 1].
Figure 1: Invasive ductal carcinoma of axillary accessory breast tissue showing malignant ductal epithelial cells forming tubules

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Case 3

A 40-year-old para 4 + 2 breastfeeding mother who presented with a 7-year history of painless left axillary swelling. Her last childbirth was 6 months before presentation. The axillary swelling measured 4 cm × 3 cm × 3 cm and was soft, mobile, and nontender. Both breasts were clinically unremarkable. The axillary tail of the breast was not connected with the axillary mass. A clinical diagnosis of lipoma was made although a differential diagnosis of accessory breast tissue was considered and the patient had excisional biopsy of the mass. Histologic sections showed normal breast acini and ducts and a diagnosis of accessory axillary breast was made.

Case 4

A 50-year-old para 3 + 0 female who presented with a fungating left axillary swelling of a year and 6 months' duration. The swelling became ulcerated a month before presentation following application of traditional herbs preparation. She also complained of significant weight loss, fever, and loss of appetite. Examination showed unremarkable left and right breasts. The axillary swelling was solitary, tender, ulcerated, and measured 6 cm × 4 cm × 3 cm. Although a draining tuberculous lymph node is a strong differential, a clinical diagnosis of lymphoma was made and an incisional biopsy was done. Histology of the biopsy revealed invasive ductal carcinoma of an accessory breast tissue.

Case 5

A 45-year-old para 6 female who presented with a 3-year history of right axillary swelling. She noticed the swelling while breastfeeding her last child. Swelling slowly increased in size and was associated with occasional mild pain and discomfort. Examination showed both breasts were unremarkable and placed in normal anatomic position. The axillary mass measured 5 cm × 4 cm × 3 cm was soft, nontender, and freely mobile. A clinical impression of a right axillary lipoma was made. The mass was excised for histopathological analysis which showed breast lobules with areas of fibrosis, adenosis, cystic dilatations, and apocrine metaplasia [Figure 2]. A histological diagnosis of fibrocystic change of the accessory breast was made.
Figure 2: Fibrocystic change of accessory axillary showing adenosis, fibrosis, cystic dilatation with apocrine metaplasia

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Case 6

A 25-year-old para 2 female who presented with a 5-year history of left axillary swelling. The swelling was painless and was noticed during her first pregnancy. The swelling subsequently increased with lactation, her menstrual cycles, and the second pregnancy. It was associated with discomfort. Clinically, both breasts were large and pendulous and devoid of any mass or nodularity. The axillary mass measured 5 cm × 3 cm × 2 cm was soft and mobile. There was no nipple or areola complex. A clinical diagnosis of accessory left axillary breast was made. Histologic examination of the excised mass confirmed ectopic breast tissue.

Case 7

A 53-year-old postmenopausal female. She is para 5 and last menstruation was 6 years before presentation. She presented with a 10-month history of left painless axillary swelling which progressively increased in size. She had no other complaints. Clinical evaluation was that of a case of metastatic axillary cancer from occult breast origin. However, clinical and mammographic examinations of both breasts revealed normal findings. An incisional biopsy showed invasive ductal carcinoma of ectopic breast tissue.

Case 8

A 27-year-old para 3. She presented with a 6-year history left axillary swelling which was first noticed during breastfeeding of her first child. There was no history of trauma or family history of similar swelling. The axillary mass measured 9 cm × 6 cm × 4 cm was mobile, lobulated, soft, with no attachment to the underlying or overlying structures. A clinical impression of lipoma of the left axilla was made. She had excisional biopsy which showed proliferating breast ducts with areas of adenosis, cystic dilatations, apocrine metaplasia, and fibrosis [Figure 3] which was diagnosed fibrocystic change of accessory breast histologically.
Figure 3: Fibrocystic change of accessory axillary showing adenosis, fibrosis, cystic dilatation with lactational change

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  Discussion Top

Accessory axillary breast tissue is the most common manifestation of polymastia, and all diseases in the normal breast also affect it. The most frequent diseases reported in the accessory breast are cancers followed by mastopathy, mastitis, fibroadenoma, and fibrocystic change.[5] Malignant tumors are the most common diseases affecting the accessory breast tissues. Badejo also reported that the incidence of malignant change in accessory breast tissue was 14%.[12] In this series, 3 (37.5%) were invasive ductal carcinoma. All the three cases had no clinical primary breast cancer, and the range of diagnoses for their axillary masses included lymphoma and metastatic disease of unknown primary. Invasive ductal carcinoma was also the most frequently reported cancer of ectopic breast tissues.[6],[7],[13] However, Giron et al. and Amsler et al. reported a case of invasive lobular carcinoma in axillary accessory breast tissues.[8],[14]

Fibrocystic change of the breast is a common complex of proliferative breast lesions affecting young to middle-aged females aged 25–45 years. Three of the accessory breast lesions in our series were fibrocystic change diseases, and the age of affectation is comparable to several reports in the anatomically located breast. Kitamura et al.[15] reported a case of bilateral axillary mastopathy with fibrocystic change occurring concurrently with a confirmed left breast invasive carcinoma. Two of our index cases presented while lactating, and this is not surprising since the accessory breast is hormonally responsive and undergoes physiologic changes of enlargement and milk secretion during pregnancy and lactation as seen in the normally positioned pectoral breast tissues. Supernumerary breast tissue may occur unilaterally or bilaterally, and the most frequent sites are the “milk line,” axilla, chest wall, and vulva. Das et al. reported a case of vulval accessory breast tissue with fibrocystic change in a 40-year-old woman who presented with an 18-month vulva mass.[16]

The aberrant breast tissue can manifest at any age, and the lesional disease present within it may not necessarily be the common breast disease for the age of patient. The three cases in this series were clinically diagnosed as axillary lipoma, a benign soft-tissue tumor of adipocytes which is quite distinct from fibrocystic disease of the breast. It is important for clinicians to consider masses or lesions along the milk line as potential primary breast lesions.

There were two cases of unremarkable breast tissues in the axillary masses in a 25-year-old lactating female and a 40-year-old female, respectively. Both cases were asymptomatic masses of variable durations. Accessory breast tissues are usually asymptomatic, except for discomfort and a source of cosmetic embarrassment to the patient.

Kajava categorized accessory breast into 8 classes based on their constituent tissues [Table 2].[17] All of our cases lacked areola and nipple and were classified as Class IV lesions. Neki et al. reported a case of Class 1 axillary breast tissue in a 32-year-old female with an axillary pendulous mass of 6.5 years duration which had a well-formed nipple and areola.[18] Further, Dabota [2] reported a case of bilateral axillary accessory breast with fully developed nipple and areola in a postpartum primipara which is a Class I disease.
Table 2: Kajava Classification of Accessory Breast Tissue

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Other common breast lesions in the accessory breast include fibroadenoma, mastitis, and phyllodes tumor which were not recorded in this series. Rong et al. reported two cases of fibroadenoma in the axillary accessory breasts of 37- and 41-year-old female patients. One of the patients noticed the mass while she was pregnant but presented 8 years later.[10] Zhang et al. reported an 8 cm mass of fibroadenoma in the axillary accessory breast and additional multiple fibroadenomas amounting to 50 in both breasts of a single patient.[9]

Ectopic breast tissue is usually present at birth and remains dormant until puberty. Many patients remain asymptomatic although frequently a palpable thickening in the affected part of the body can be observed during monthly premenstrual changes. Most often, the presence of ectopic breast tissue is only noticed during pregnancy or lactation due to hormonal stimulations. The occurrence of ectopic breast is due to failure of regression and development of milk line after normal development of the breast in the pectoral area. In the presence of these symptoms, the diagnosis is usually clinically easy; however, in case of Kajava Classes III, IV, VII, and VIII, the diagnosis is readily missed and differential diagnoses of other common soft-tissue tumors entertained. Symptoms in axillary accessory breast tissue usually worsen with subsequent pregnancies, causing increased pain, local irritation, restriction of arm movement, and anxiety.

Fine-needle aspiration (FNA) technique and routine radiological investigative procedures of the breast are applicable to accessory breast tissue. Standard mammograms do not usually show ectopic breast tissue because of its location; however, with special positioning of the patient, these lesions can be imaged. In our series, none of the patients had FNA or radiological study done which could have contributed to the high rate of missed diagnosis. Samaila [19] also reported a case of accessory axillary breast mass with atypical ductal cells using FNA technique in a patient with clinical Stage III breast cancer.[19] Sibel et al. documented a case of inframammary fold accessory breast cancer mammographically.[7]

The treatment of accessory axillary breast depends on the specific underlying pathology. Most cases of benign lesions are managed conservatively with excisional biopsy while malignant cases will require a wide local excision combined with radiotherapy and/or chemotherapy.

Accessory axillary breasts are relatively uncommon and are often misdiagnosed as soft-tissue tumors. The most common disease seen in these accessory breasts was cancer and fibrocystic change. A high index of suspicion is required to detect these lesions early to offer the best treatment options. Accessory breast should be entertained in differential diagnosis of axillary masses.[16]

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/ her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.


We would like to acknowledge the entire staff of the Department of Pathology, Ahmadu Bello University Teaching Hospital, Zaria.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

Geddes DT. Inside the lactating breast: The latest anatomy research. J Midwifery Womens Health 2007;52:556-63.  Back to cited text no. 1
Dabota YB. Bilateral accessory breast: A case report. Jos J Med 2012;6:32-3.  Back to cited text no. 2
Nirmala JL, Gayathri M, Suguna S, Thirupurasundari R. Accessory breast tissue in the axilla in a puerperal woman – Case study. Acta Medica Medianae 2010;49:45-8.  Back to cited text no. 3
Godoy-Gijón E, Yuste-Chaves M, Santos-Briz A, Esteban-Velasco C, de Unamuno-Pérez P. Accessory breast on the vulva. Actas Dermosifiliogr 2012;103:229-32.  Back to cited text no. 4
Pfeifer JD, Barr RJ, Wick MR. Ectopic breast tissue and breast-like sweat gland metaplasias: An overlapping spectrum of lesions. J Cutan Pathol 1999;26:190-6.  Back to cited text no. 5
Boulaamane L, Khanouss B, El Ghissassi B, Rabti HM, Errihani H. Carcinoma originating from aberrant breast tissue: Case report and review of the literature. J Integr Oncol 2013;3:110.  Back to cited text no. 6
Sibel K, Senem T, Ugur T, Meral K, Sehsuvar G, Ozlem S, et al. Carcinoma originating from aberrant breast tissue. A case report and review of the literature. Tumori 2008;94:440-3.  Back to cited text no. 7
Giron GL, Friedman I, Feldman S. Lobular carcinoma in ectopic axillary breast tissue. Am Surg 2004;70:312-5.  Back to cited text no. 8
Zhang RR, Bevan S, Sun P, Lu JZ, Peng Y. Unusual presentation of multiple fibroadenomas in bilateral breasts and axillary accessory breast. Breast Cancer (Auckl) 2012;6:95-9.  Back to cited text no. 9
Rong XY, Zhu Q, Jia WX, Ma T, Fang YQ, Zhou YJ, et al. Fibroadenoma of the ectopic axillary breast tissue: Sonographic appearances. Open J Clin Diagn 2014;4:205-11.  Back to cited text no. 10
Dauda AM, Ojo EO. Fibrocystic change in axillary polymastia with absent nipple: Report of a case at Federal Medical Center Gombe Nigeria. Adv Lab Med Int 2011;1:21-4.  Back to cited text no. 11
Badejo OA. Fungating accessory breast carcinoma in Nigerian women. Trop Geogr Med 1984;36:45-9.  Back to cited text no. 12
Shariful Alam AM, Shamima A. Carcinoma of the ectopic breast. J Enam Med Col 2013;3:47-9.  Back to cited text no. 13
Amsler E, Sigal-Zafrani B, Marinho E, Aractingi S. Ectopic breast cancer of the axilla. Ann Dermatol Venereol 2002;129:1389-91.  Back to cited text no. 14
Kitamura K, Kuwano H, Kiyomatsu K, Ikejiri K, Sugimachi K, Saku M. Mastopathy of the accessory breast in the bilateral axillary regions occurring concurrently with advanced breast cancer. Breast Cancer Res Treat 1995;35:221-4.  Back to cited text no. 15
Das S, Roy AK, Kar C, Giri PP. A rare case of fibrocystic disease at vulval accessory breast tissue. J Indian Med Assoc 2007;105:652-3.  Back to cited text no. 16
Kajava Y. The proportions of supernumerary nipples in the Finnish population. Duodecim 1915;31:143-70.  Back to cited text no. 17
Neki NS, Ishu S, Himanshu G, Tamil M. Accessory breast tissue in the axilla presenting as a pendulous mass: A case report. JIMSA 2014;27:31-2.   Back to cited text no. 18
Samaila MO. Advanced breast cancer associated with atypical cells in accessory breast. Saudi Med J 2008;29:458-9.  Back to cited text no. 19


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2]


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