Galactoceles or Milk Cysts: What You Should Know

Galactoceles or milk cysts are present in up to 4% of infants. Find out what they are, their causes, and how they're treated.

Reviewed and approved by el médico Diego Pereira.

Written by Josberth Johan Benitez Colmenares

Last update: 15 February, 2023

Galactoceles are benign milk cysts that develop almost exclusively in lactating women. They’re also known as lactoceles or lacteal cysts. They’re part of what experts call benign breast and lactation disorders, among which breast lumps hold a particular place.

It’s estimated that up to 4% of women develop a galactocele, although the number could be higher. This is because many cysts aren’t detected by patients, and when they’re detected by specialists, they’re usually not reported due to their benign nature. Today we’ll review their characteristics, causes, and treatment options.

The characteristics of galactoceles or milk cysts

The term galactocele comes from the Greek locutions galatea, meaning “milky white”, and cele, meaning “bag”. Although milk cysts can form in several places, the truth is that they tend to develop in the retroareolar region of the breasts. They’re characterized by small swollen areas that don’t cause pain.

They begin with a small lump in one or both breasts, which is insidious and increases progressively. There are no other symptoms such as pain or fever, although they can cause difficulty breastfeeding (especially in first-time mothers). The cysts are usually solitary, firm, free-moving, and can easily be mistaken for a breast tumor.

According to experts, milk cysts occur more frequently in lactating women in the postpartum period, although they can also appear in other groups. Cases have been reported in children and infants and also in young men. In any case, most milk cysts develop in women during the lactation period.

They’re much more frequent in women with dense breasts and can be detected through ultrasound tests. Breast ultrasound and mammography are the most used techniques, with a predilection for the former.

In the process, other possible explanations can be ruled out, such as breast abscesses, breast cysts, hematomas, adenomas in infancy, fibrocystic changes, and breast carcinoma.

The cyst contains milk or milky substances, and only a few cases are associated with infection. This is because the milk that makes them up is sterile, so complications in this regard are very rare. Despite this, they should be evaluated by a specialist to avoid interrupting the lactation process.

The causes of galactoceles or milk cysts

As experts point out, most galactoceles or milk cysts can be explained by three triggers: Ductal obstruction, prolactin stimulation, and secretory mammary epithelium. Let’s look at all these variables in detail:

• Ductal obstruction: Cases of galactoceles or milk cysts have been reported after breast augmentation surgery. Periareolar incisions are pointed out as the possible culprits, as these can cause lesions in the ducts that lead to their obstruction. Although less common, they can also appear in inframammary approaches.
• Prolactin stimulation: The phenomenon can manifest in infants and children due to the transplacental passage of prolactin. In adult men, it can occur due to episodes of hyperprolactinemia, often related to hypogonadotropic hypogonadism.
• Secretory mammary epithelium: The most affected group is women during the third trimester of pregnancy, during lactation, or after it. The hormonal influence of chorionic gonadotropin plays a major role, especially in women with difficulty breastfeeding, who’ve followed a treatment based on birth control pills for a while, or when breast milk doesn’t empty.

These are the main triggers of galactoceles or milk cysts. So far, genetic predisposition has been ruled out, so there are no genetic risk factors that encourage their appearance. All cases are benign and aren’t associated with further complications, although a professional should be consulted to rule out other explanations and assess the presence of a milk cyst.

Treatment options

Galactocele treatment is usually conservative. Most milk cysts disappear after lactation stops. This is because the hormonal changes related to pregnancy recede. Considering that they’re not painful and don’t usually cause complications, doctors and patients often decide to hold off on treatment. In other contexts, you can resort to the following:

• Fine needle aspiration: In lactating women with particularly large cysts, fine needle aspiration may be used. This is done with the complement of gram-positive antibiotics, in order to avoid complications after the procedure. Cases of recurrence of extracted cysts are rare.
• Prescription of dopamine agonists: Cases not related to lactation (breast enlargement, for example) can be treated with drugs such as bromocriptine. This and others available are useful for inhibiting milk production.
• Surgery: Some episodes may be related to major complications, such as prolactinoma. This is a tumor that increases the production of prolactin and can be treated by means of surgery, radiotherapy, and medication intake (bromocriptine and cabergoline).

Regardless of these options, patients should be aware that the prognosis is almost always excellent; so many specialists will choose to wait for the cysts to disappear on their own. Breast massage during pregnancy and lactation can be used as a preventive method, especially in women with a large breast volume.