Galactocele (Milk Cyst)

What a galactocele is

Milk is made in small glands (lobules) and travels through ducts to the nipple. If a duct becomes blocked, milk can pool behind the blockage and form a fluid-filled cyst lined by duct cells. Over time the water is absorbed, and the contents can thicken into a creamy or even cheese-like material.

Galactoceles are the most common benign breast lump during breastfeeding. They are much less common than blocked ducts, which usually clear within a day or two.

Symptoms

• A smooth, round or oval lump, often 1 to 5 cm across.
• Usually painless, though larger ones can feel tight or tender.
• The lump may get bigger before a feed and smaller after.
• Squeezing it sometimes releases milk from the nipple.
• No redness or fever unless it becomes infected.

Galactocele vs other breast lumps when breastfeeding

Pregnancy-associated breast cancer is uncommon, but delays in diagnosis happen because lumps are assumed to be milk-related. Any lump that does not go away within about 2 weeks deserves imaging.

Causes and risk factors

• Breastfeeding, especially when feeds are irregular or a breast is not drained well.
• Weaning, when milk builds up as feeds stop.
• Pressure on the breast from tight bras or sleeping position.
• Rarely, men and infants can develop galactoceles linked to hormones or medicines.

Diagnosis

1. Breast exam by a doctor.
2. Ultrasound: the first-choice test while breastfeeding. A galactocele appears as a cyst, sometimes with a fat-fluid level or mixed contents, depending on how old the milk is. Older ones can look solid and complex.
3. Needle aspiration: a fine needle draws out the contents. Milky fluid confirms the diagnosis and also treats it.
4. Mammogram: sometimes used. A galactocele may show a characteristic fat-fluid level.
5. Biopsy: if the ultrasound shows solid parts or the lump does not behave as expected.

Treatment

• Watchful waiting: small, painless galactoceles often resolve on their own after weaning.
• Needle aspiration: drains the milk, relieves pressure and confirms the diagnosis. It may need repeating if the cyst refills.
• Continue breastfeeding: in most cases it is safe and helpful to keep feeding from that side.
• Antibiotics: only if the cyst becomes infected. Infected collections may need drainage, like an abscess.
• Surgery: rarely, for a large galactocele that keeps refilling or when the diagnosis is uncertain.

Avoid deep, forceful massage of breast lumps. Current breastfeeding guidance favors gentle handling, cold packs and anti-inflammatory measures over aggressive massage, which can inflame tissue.

Outlook

Galactoceles are harmless and do not turn into cancer or increase breast cancer risk. Most disappear within weeks to months, especially after weaning. They can recur in the same or a later breastfeeding period.

Frequently asked questions

What is a galactocele?

A galactocele is a cyst filled with breast milk. It forms when a milk duct becomes blocked and milk collects behind it, usually during breastfeeding or after weaning. It is benign, typically painless, and often goes away on its own or after the milk is drained with a needle.

Can I keep breastfeeding with a galactocele?

Yes, in most cases. A galactocele is not harmful to your baby and breastfeeding can usually continue on both sides. If the lump is painful, red or you have a fever, see a doctor to check for infection, which may need antibiotics or drainage.

How is a galactocele different from a blocked duct?

A blocked duct is a tender, firm area that usually clears within a day or two with continued feeding. A galactocele is a defined cyst that lasts for weeks or months, often without pain. Ultrasound or drawing out milky fluid with a needle tells them apart.

Does a galactocele go away on its own?

Often, yes. Many galactoceles shrink gradually, especially after you stop breastfeeding and milk production winds down. If the lump is large, uncomfortable or does not go away, a doctor can drain it with a needle, which usually resolves it.

Can a galactocele be cancer?

No. A galactocele is a benign milk cyst. However, breast cancer can occur during pregnancy and breastfeeding, and some lumps look similar on examination. That is why a breast lump lasting more than 1 to 2 weeks should be checked with ultrasound.