Galactocele · What Is It, Signs and Symptoms, Treatment, and More

Published: Mar 31, 2026

Author: Nikol Natalia Armata, MD •

Editor: Alyssa Haag, MD•

Editor: Józia McGowan, DO•

Editor: Kelsey LaFayette, DNP, ARNP, FNP-C

Illustrator: Abbey Richard, MSc

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What is a galactocele?

A galactocele refers to a rare, benign breast lesion characterized by the cystic enlargement of the mammary glands that occurs due to the accumulation of milk within a blocked duct. It typically occurs during or after lactation. Rarely, galactoceles can develop many years after the end of lactation. Clinically, galactoceles present as firm, well-defined, and usually non-tender masses, which may mimic the appearance of a solid tumor.

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What causes a galactocele?

The formation of a galactocele is the result of obstruction of a lactiferous duct, a duct that carries milk from the lobes of the breast to the nipple. This blockage prevents the normal drainage of milk, leading to its accumulation and subsequent retention cyst formation. The most common cause of a galactocele is the physical blockage of the duct, which can occur due to thickened milk, inflammation, or scarring within the ductal system. Hormonal changes associated with lactation, such as elevated prolactin levels, may increase the density of milk, contributing to ductal obstruction. Trauma or pressure on the breast, such as from tight clothing or poor positioning during breastfeeding, can compress ducts and impair milk flow, further predisposing to galactocele formation. Additionally, abrupt cessation or infrequent breastfeeding can cause milk stasis, creating an environment where milk components can accumulate and block the ducts. Rarely, an underlying infection or mastitis can lead to the formation of granulation tissue, narrowing the ductal lumen and causing a galactocele.

What are the signs and symptoms of a galactocele?

A galactocele typically presents as a painless, palpable breast lump. This lump is usually well-described, round, and movable, with a consistency that can range from soft to firm, depending on the composition of the fluid within the cyst. Galactoceles are generally not associated with signs of infection, such as erythema, warmth, or systemic symptoms like fever, which helps differentiate them clinically, from mastitis or breast abscesses. These cysts usually range from 1 to 6 centimeters (cm) in diameter. The size of a galactocele may fluctuate, often enlarging when milk production is high or immediately after breastfeeding due to retained milk in the ductal system. In some cases, slight discomfort or tenderness can be felt if the galactocele applies pressure on surrounding tissues, though pain is not a prominent feature. Additionally, there is usually no significant nipple discharge, although, if present, it may be milky due to the cyst's contents.

How is a galactocele diagnosed?

A galactocele is diagnosed through a combination of clinical evaluation, imaging, and occasionally interventional procedures. If a painless, palpable, and mobile breast lump is identified during clinical examination in lactating individuals, often further investigation is suggested. It’s important to differentiate a galactocele from other breast masses, such as abscesses or malignancies. Ultrasound is the preferred imaging modality for diagnosing a galactocele, as it reveals a well-circumscribed cystic lesion with homogenous, low-level internal echoes, characteristic of milk content. Mammography may also be used but is less common due to its limited utility in younger, lactating individuals. Fine-needle aspiration (FNA) can be performed to obtain fluid from the cyst, which typically will identify thick, milky material, confirming the diagnosis. Cytological examination of the aspirated fluid can further distinguish a galactocele from more serious conditions such as abscesses or malignancies.

Biopsy and histological examination are not routinely required to confirm the diagnosis of a galactocele; however, when performed, they typically reveal cystic spaces lined by flattened cuboidal epithelium, showing evidence of pressure necrosis, chronic inflammation, and sometimes active apocrine gland involvement.

How is a galactocele treated?

The treatment of a galactocele primarily depends on the size of the cyst, the presence of symptoms, and the individual's lactation status. Many cases are managed conservatively with observation, especially if the cyst is small, asymptomatic, or not causing discomfort. In cases where the galactocele is large, symptomatic, or causing significant discomfort, needle aspiration may be performed to remove the trapped milk and relieve symptoms. Aspiration is typically guided by ultrasound to ensure precision and is often effective; however, the cyst may recur, necessitating repeated aspirations. If aspiration is unsuccessful or if the galactocele frequently recurs, surgical excision may be considered, particularly if the condition impacts the patient's quality of life or raises concerns for potential malignancy. In rare cases where secondary infection occurs, antibiotics may be required.

What are the most important facts to know about galactoceles?

Galactoceles are benign breast cysts that form when a lactiferous duct is blocked, causing milk build-up and development of a palpable lump. Typically occurring during or shortly after lactation, these cysts range from 1-6 cm in diameter and present as firm, mobile, non-tender masses, occasionally causing discomfort due to pressure on surrounding tissues. Diagnosis is typically made through ultrasound, with fine-needle aspiration for confirmation. Treatments include observation for asymptomatic cases or needle aspiration for larger, symptomatic cysts. Surgical excision may be required if recurrent or symptomatic.

Key Takeaways

Definition	A galactocele refers to a rare, benign breast lesion characterized by the cystic enlargement of the mammary glands that occurs due to the accumulation of milk within a blocked duct, typically during or after lactation.
Cause	-Obstruction of a lactiferous duct → milk accumulation and retention cyst formation -Due to: -Thickened milk (hormonal changes) -Inflammation of ductal system -Scarring of ductal system -Trauma/pressure on the breast -Abrupt cessation or infrequent breastfeeding (milk stasis) -Infection/mastitis
Signs and symptoms	-Palpable breast lump that is: -Painless -Slight discomfort/tenderness from pressure on surrounding tissues -Well-described -Round -Movable -Soft-firm consistency -Fluctuating in size, usually ranging from 1 to 6 cm -No associated signs of infection or significant nipple discharge
Diagnosis	-Clinical evaluation: painless, palpable, mobile breast lump in lactating individuals -Imaging: -Ultrasound -Mammography -Interventional procedures -Fine-needle aspiration (FNA) with cytology
Treatment	-Small, asymptomatic cyst → observation -Large, symptomatic cyst → ultrasound-guided needle aspiration -If frequent recurrence / unsuccessful aspiration → surgical excision -Secondary infections → antibiotics

References

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Haliloglu N, Ustuner E, Ozkavukcu E. Breast ultrasound during lactation: Benign and malignant lesions. Breast Care (Basel). 2019;14(1):30-34. doi:10.1159/000491781

Langer A, Mohallem M, Berment H, et al. Breast lumps in pregnant women. Diagn Interv Imaging. 2015;96(10):1077-1087. doi:10.1016/j.diii.2015.07.005

Ramani SK, Rastogi A, Nair N, Shet TM, Thakur MH. Hyperechoic lesions on breast ultrasound: All things bright and beautiful? Indian J Radiol Imaging. 2021;31(1):18-23. doi:10.1055/s-0041-1729124

Winkler JM. Galactocele of the breast. The American Journal of Surgery. 1964;108(3):357-360. doi:https://doi.org/10.1016/0002-9610(64)90352-6