Galactocele

A galactocele is a benign, fluid-filled cyst containing milk or milky fluid, caused by obstruction of a lactiferous duct. It occurs most commonly in lactating or recently lactating women.

It is a common, generally straightforward and readily managed benign breast condition. It must be distinguished accurately from other, potentially more concerning causes of a breast lump in pregnancy or lactation, the generally reassuring context in which it characteristically presents.

Pathophysiology

• Obstruction of a lactiferous duct prevents normal milk drainage from the affected ductal system. The cause may be local inflammatory change, scarring from previous breast surgery or infection, or simple mechanical obstruction.
• Milk accumulates progressively proximal to the obstruction and forms the characteristic fluid-filled cyst.
• The condition most commonly develops during active lactation. It can also occur after breastfeeding stops, because of continued, residual secretory activity in the affected ductal segment despite the broader reduction in lactation.
• The fluid evolves over time, from a liquid, milk-like consistency in early presentations to a thicker, creamy or cheese-like consistency in longer-standing lesions. This reflects progressive concentration and, in some cases, partial resorption of the fluid component.

• A smooth, mobile, typically painless or mildly tender palpable breast lump in a woman who is currently breastfeeding or has recently stopped is the characteristic presentation. The lump may fluctuate in size in relation to feeding patterns.
• The lesion is generally well-circumscribed and freely mobile, without the skin changes, fixation or axillary lymphadenopathy that would raise concern for a more serious diagnosis.
• Careful clinical assessment remains important, because an alternative diagnosis remains a generally low but real possibility even in this reassuring context.
• Secondary infection can occur, producing localised erythema, increasing tenderness and, in some cases, systemic features of infection. It is a recognised complication requiring specific additional management.
• Current or recent breastfeeding is an essential element of the history. It directly informs the differential diagnosis and the diagnostic approach.

• Clinical assessment of the characteristic presentation and lactation history, together with ultrasound, supports confident diagnosis in the great majority of presentations. Ultrasound is the preferred initial imaging modality in this generally younger patient population.
• Ultrasound typically shows a well-defined, cystic lesion with characteristic internal echogenicity reflecting its milky fluid content.
• Fine needle aspiration confirms the diagnosis through aspiration of characteristic milky fluid, and at the same time drains the lesion. It is a valuable, commonly used diagnostic and management approach.
• Where clinical or imaging findings are atypical, or there is any diagnostic uncertainty, pursue full triple assessment to exclude an alternative, more concerning diagnosis before accepting a galactocele diagnosis.

• Fine needle aspiration gives diagnostic confirmation and symptomatic relief through drainage of the accumulated fluid. It is the standard, generally effective initial management for a symptomatic or diagnostically uncertain galactocele.
• Recurrence after initial aspiration is relatively common, because of the underlying, persistent ductal obstruction and continued secretory activity of the lactating breast. Repeat aspiration is an appropriate, generally effective approach.
• Continued breastfeeding, where the woman wishes to continue, is generally safe and appropriate. It does not require cessation or modification of feeding from the affected breast, though some women find feeding from the affected side more comfortable after aspiration of a larger, more symptomatic lesion.
• Secondary infection requires appropriate antibiotic therapy, following broadly similar principles to those for lactational mastitis, together with continued or, where required, more definitive drainage of the infected collection.
• Surgical excision is rarely required. It is reserved for persistent, recurrent, or particularly large or symptomatic lesions not adequately managed with repeated aspiration alone, or where diagnostic uncertainty remains after standard non-surgical assessment.
• Reassure the woman about the benign, generally self-limiting nature of the condition and its generally excellent prognosis. Explain the practical management options should recurrence occur.