Accessory Breast Removal · Complete mammary tissue removal + fat aspiration + minimal-incision surgery
"My underarm strangely swells and aches before my period." "My underarm bulges when I wear certain tops, and it bothers me." — these are complaints we hear often. Many patients assume it's simply underarm fat, but in a significant number of cases it turns out to be an accessory breast.
An accessory breast is composed of developed mammary tissue, unlike ordinary fat — so liposuction alone leads to recurrence. The mammary tissue itself must be removed, and accurate differentiation of the cause is what makes recurrence-free results possible. This article walks through the difference between accessory breasts and simple fat, the two causes, and Bong Bong Plastic Surgery's 3-principle surgical approach.
The 3-minute summary
- Procedure
- Accessory Breast Removal
- Causes
- ① Congenital mammary tissue development ② Acquired fat accumulation
- Surgical principles
- Complete mammary tissue removal + fat aspiration + ≤2 cm minimal incision
- Surgery time
- About 1 hour · general anesthesia · same-day discharge
- Recovery
- Return to daily life in 2–3 days · suture removal at day 7
What is an accessory breast
An accessory breast is a small breast that develops between the breast and underarm from proliferation of mammary tissue1. The name (Korean: 부유방, "accessory breast") refers to additional breast tissue outside the normal breast. In severe cases, the accessory breast disrupts the balance of a beautiful breast contour and, through structural changes in mammary tissue, may lead to other breast-related conditions.
An accessory breast is mammary tissue proliferating outside the normal breast. That's why the mammary tissue itself must be removed — otherwise it recurs.
Dr. Seongsoo Park · Chief Director, Bong Bong Plastic Surgery Clinic
Accessory breast vs. simple underarm fat
The two conditions may look similar externally but have completely different tissue composition. Misdiagnosis leads to recurrence or unnecessary surgery, so accurate differentiation matters.
| Comparison | Simple underarm fat | Accessory breast (mammary tissue) |
|---|---|---|
| Composition | Subcutaneous fat only | Mammary tissue + surrounding fat |
| Menstrual cycle influence | None | Swelling and pain occur |
| Discharge | None | Possible |
| Texture | Soft | Firm lump palpable |
| Resolvable by liposuction alone | Yes | No (recurs if mammary tissue remains) |
Two causes
Accessory breasts are divided into congenital and acquired categories, and the surgical approach shifts slightly depending on the cause.
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CASE 01
Congenital mammary tissue development
During embryonic breast development, additional mammary tissue forms in the underarm area. It becomes prominent after puberty as mammary tissue is activated, and it responds to hormonal changes from menstruation, pregnancy, and lactation.
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CASE 02
Acquired fat accumulation
Fat protrudes in the underarm area due to acquired accumulation — weight gain, hereditary fat distribution, or posture. In this case there is no mammary tissue, so it can be resolved with liposuction alone.
In the clinic, palpation and ultrasound confirm the presence of mammary tissue. If mammary tissue is present and only liposuction is performed, recurrence typically occurs within 1–2 years2. Conversely, performing an excisional procedure on simple fat leaves an unnecessary scar and unnecessary invasiveness. Accurate differentiation is the starting point of surgical planning.
Who benefits from removal
Consider an accessory breast if you experience the following:
- A lump beneath the underarm
- A mass in the underarm area
- Unusual sensations in the underarm around menstruation
- Discharge from the underarm
- A sense that the underarm mass has grown after pregnancy or breastfeeding
- Self-consciousness because the underarm protrudes in sleeveless clothing
If the underarm lump becomes larger, harder, or painful, it may not be an accessory breast but a lymph node abnormality or tumor. Confirming the cause with ultrasound before consultation is the safer path.
The Bong Bong 3 principles
Bong Bong Plastic Surgery's accessory breast removal follows 3 principles:
Complete mammary tissue removal
If mammary tissue remains, the accessory breast recurs. Complete removal of the accessory mammary tissue is the core of treatment.
Fat aspiration around the mammary tissue
Fat above and around the mammary tissue is aspirated together. Clearing the overlying fat is what produces a smooth underarm contour.
≤2 cm minimal-incision technique
A minimal incision of 2 cm or less is placed within the natural underarm crease so that the scar is inconspicuous.
Why complete mammary tissue removal matters
The most common cause of recurrence is incomplete mammary tissue removal. Because mammary tissue is hormone-responsive, even a small remnant will enlarge again with menstruation, pregnancy, or lactation. At Bong Bong Plastic Surgery, we excise mammary tissue completely from the superficial to the deep layers, and confirm the absence of residual tissue through pathological examination after removal3.
Surgical process and recovery
Accessory breast removal is a short procedure of about 1 hour, performed under general anesthesia with no hospitalization required and same-day discharge. Sutures are removed at day 7, and return to daily life is possible from 2–3 days after surgery.
- STEP 01
Detailed Consultation · Palpation
Presence of mammary tissue verified. Ultrasound used if necessary.
- STEP 02
Safety Workup
Blood work, ECG, and other preoperative diagnostics.
- STEP 03
Design Marking
Incision location, mammary excision extent, and fat aspiration zone planned.
- STEP 04
Surgery (~1 hour)
General anesthesia. Complete mammary excision + surrounding fat aspiration.
- STEP 05
Aftercare
Suture removal at day 7. Compression band worn for 4 weeks.
Recovery timeline
- Day of surgery — Discharge after anesthesia recovery
- Days 2–3 — Return to daily life (office-based work)
- Day 7 — Suture removal, showering permitted
- Weeks 2–4 — Compression band worn; avoid overhead arm motions
- Week 4 — Light exercise resumes
- Week 6 — Vigorous exercise and swimming permitted
- Months 3–6 — Scar stabilization and final shape settling
Wondering if your underarm lump is an accessory breast? Check with a free consultation.
Diagnosed personally by the chief director of Bong Bong Plastic Surgery. Consultation and diagnostics are complimentary.
Frequently Asked Questions
QWhen can I return to daily life?
QHow is an accessory breast different from simple underarm fat?
QCan it recur after removal?
QHow noticeable is the scar?
QDoes it affect breastfeeding?
- Anatomy Accessory Breast (Polymastia) — embryological definition.
- Recurrence Accessory breast recurrence — residual mammary tissue.
- Pathology Accessory-breast-derived pathology — fibroadenoma and breast cancer cases.
Closing thoughts
An accessory breast may seem like a purely cosmetic concern, but because it is hormone-responsive tissue, leaving it untreated leads to repeated swelling and pain with each menstrual cycle — and, rarely, to accessory-breast-derived conditions. Rather than dismissing it as "probably just fat," we recommend having it accurately assessed at least once.
To review differential diagnosis and surgical options together, see the clinical columns on the Bong Bong Plastic Surgery Blog. If you'd like to address breast volume and underarm contour together, a combined approach with Hybrid Augmentation or BiVol 4th-generation breast augmentation is also worth considering.