Galactocele: Definition, Diagnosis, and Management
A galactocele is a benign milk-filled cyst of the breast that typically occurs during pregnancy or lactation when a milk duct becomes obstructed. 1
Clinical Characteristics
- Galactoceles are the most common benign breast lesions during the breastfeeding period 2
- They typically present as a palpable mass in the breast of pregnant or lactating women 1
- They can occasionally occur in unusual locations such as axillary accessory breast tissue 2
- Long-standing galactoceles can rarely undergo crystallization (crystallizing galactocele), which may mimic malignancy clinically and sonographically 3, 4
Pathophysiology
- Galactoceles form when a mammary duct becomes obstructed and overfilled with milk 5
- They are most commonly associated with pregnancy and lactation, but rare cases have been reported in non-lactating women and men 5
- In some cases, hyperprolactinemia (such as from a prolactinoma) may contribute to galactocele formation even in the absence of pregnancy or lactation 5
Diagnostic Approach
- Ultrasound is the first-line imaging modality for evaluating breast masses in pregnant and lactating women 1
- On ultrasound, galactoceles typically appear as well-defined cystic lesions, though they may occasionally have suspicious features 1, 2
- Galactoceles can be definitively diagnosed through fine needle aspiration (FNA), which typically yields milky fluid 6, 4
- FNA is both diagnostic and therapeutic, often resolving the lesion 2
Imaging Characteristics
- Breast ultrasound has 100% sensitivity for diagnosing breast masses in pregnant and lactating women 1
- Galactoceles are usually identified as benign cystic lesions on ultrasound, allowing for confident diagnosis without further evaluation 1
- However, some galactoceles may have atypical features that can mimic suspicious lesions, particularly crystallizing galactoceles 3, 4
Management
- When a galactocele is definitively diagnosed on imaging, no further intervention is typically needed 1
- For symptomatic or large galactoceles, ultrasound-guided aspiration can provide both diagnostic confirmation and therapeutic relief 6, 2
- Fine needle aspiration typically yields milky fluid that is diagnostic of galactocele 6
- In crystallizing galactoceles, aspiration may reveal crystals of varying sizes and shapes that can be confirmed with special stains 6, 4
Clinical Pearls and Pitfalls
- Galactoceles must be differentiated from other breast masses, including malignancy, as breast cancer can occur during pregnancy and lactation 1
- Long-standing galactoceles may crystallize and mimic malignancy both clinically and on imaging 3, 4
- Pregnancy-associated breast cancer (PABC) can have falsely benign features on imaging, presenting with relatively circumscribed margins and posterior acoustic enhancement, similar to benign lesions 1
- When evaluating breast masses in pregnant or lactating women, it's important to remember that over 80% of palpable masses biopsied in this population are benign 1