Accessory Breast on Back: A Very Rare Presentation

By Rohan Habib, Ulas Khan, Ayesha Ayub

Affiliations

1. Department of General Surgery, Jinnah International Hospital, Abbottabad, Pakistan

ABSTRACT
Ectopic breast tissue (EBT) is an uncommon congenital condition that occurs due to the incomplete regression of the mammary ridge during embryogenesis. Accessory breast tissue is most frequently found in the axilla and is usually in the region of the mammary ridge line from the axilla towards the groin. The occurrence on the back is extremely rare. Herein, a case of a 20-year female with an accessory breast on her back is presented, which was excised due to recent enlargement. The patient underwent surgical excision and had an uneventful postoperative recovery. Histopathological examination confirmed benign breast tissue without any evidence of malignancy.

Key Words: Accessory breast, Ectopic breast tissue, Surgical excision, Benign breast lesion.

INTRODUCTION

Accessory breast tissue, also known as polymastia, is a rare congenital anomaly that results from the failure of mammary ridge regression during foetal development. It is a rare condition that affects 0.4-6% of women.¹ In the Asian population, the incidence of accessory breast ranges from 2-6%.² They are mostly present in the region of the axilla.³ However, ectopic breast tissue outside the mammary ridge line is exceedingly rare. It can occur in unusual sites such as the buttocks, back, neck, flank, and face.⁴ Excision of the ectopic breast tissue is recommended.⁵ This case report highlights the clinical presentation, diagnosis, and surgical management of a young female with an accessory breast on her back.

CASE REPORT

A 20-year female presented in October 2024 with a progressively enlarging lump on her back over the past year. There was no history of pain, discharge, or systemic symptoms. The patient reported noticing the lump since childhood, but its recent increase in size prompted medical consultation.

On examination, a well-defined, soft, non-tender mass measur-ing approximately 15×10 cm was noted on the back, lateral to the midline. The overlying skin was unremarkable, except for two nipples present on the mass (Figure 1). No lymphadenopathy was detected. The patient had no family history of breast malignancy or congenital anomalies. Ultrasound of the lesion revealed a well- circumscribed hypoechoic mass suggestive of ectopic breast tissue.

No cystic or suspicious features were identified. Given the recent growth and the patient’s cosmetic concerns, surgical excision was planned. The patient underwent complete excision of the mass under general anaesthesia after a week from diagnosis. The specimen was sent for histopathological evaluation (Figure 2). The postoperative course was uneventful, and the patient was discharged on the second postoperative day after removal of the redivac drain with no complications. A follow-up was advised on the 10^th postoperative day for stitch removal. The patient followed up on the appointed day, and the wound was examined, which showed no signs of infection, and stitches were removed. The microscopic examination report was available after a month and confirmed the presence of benign breast tissue comprising lobules and ducts, without atypia or malignancy. No evidence of fibrocystic changes, dysplasia, or neoplastic transformation was observed. The patient was discharged from surgical care subsequently.
 

Figure  1:  Preoperative picture. Accessory breast on the back with two nipples.

Figure  2:  Postoperative  specimen.

DISCUSSION

Ectopic breast tissue is rare and most commonly seen in the axillary region. Ectopic breast on the back is an exceedingly unusual presentation. It is essential to differentiate accessory breast tissue from other cutaneous lesions, such as lipomas, epidermoid cysts, or soft tissue tumours. Although most cases remain asymptomatic, hormonal influences can lead to periodic changes, enlargement, and discomfort. Malignant transformation in ectopic breast tissue has been reported, but it is rare.⁶ Surgical excision is the preferred treatment in symptomatic or cosmetically concerning cases. Accessory breast tissue should be considered in the differential diagnosis of soft tissue masses in unusual locations. Surgical excision provides both diagnostic confirmation and symptomatic relief. Histopathological examination is crucial to rule out malignancy. This case emphasises the importance of recognising this rare entity to ensure proper management and follow-up.

PATIENT’S  CONSENT:
Written consent was taken from the patient for publication of this case report.

COMPETING  INTEREST:
The  authors  declared  no  conflict  of  interest.

AUTHORS’  CONTRIBUTION:
RH: Diagnosis, study design, literature review, and drafting.
UK: Diagnosis, study design, and literature review.
AA: Literature review and proofreading.
All authors approved the final version of the manuscript to be published.

REFERENCES

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