Breast lumps in a lactating woman may or may not be related to breastfeeding. Differential diagnoses include: <sup>1-4


Blockage of milk ducts (blocked ducts or plugged ducts) is a localized area of milk stasis within the milk ducts that cause distension of mammary tissue. It presents with sudden onset of a painful breast lump without systemic symptoms. Sometimes, a blockage of a milk duct opening at the nipple results in the appearance of a white dot, white bleb or blister at the nipple. Diagnosis is clinical. There are 3 possible outcomes for blocked ducts: resolving within 24-48 hours, progressing to mastitis or developing into a galactocele. Transient reduction of milk production is common in acute blocked ducts.

Mastitis is a localized inflammation of the breast. The inflammation may or may not involve a bacterial infection. The usual clinical presentation of mastitis is an erythematous, tender and hot wedge-shaped swelling of the breast, associated with systemic symptoms of fever (temperature of 38.5°C or higher), chills, headache, malaise and myalgia. It is often the result of a prolonged breast engorgement or blockage of milk ducts. The diagnosis is usually made clinically. During the acute phase of mastitis, transient reduction of milk production is common.</sup>

Breast abscess is a localized collection of pus within the breast tissue, often preceded by mastitis. About 3% of women who experience breast inflammation will develop an abscess.⁵ The early symptoms and signs of a breast abscess are similar to those of mastitis but a breast abscess is usually much more painful and with more intensely erythematous skin. The fever may have subsided and fluctuation of the lump may not be obvious, depending on the timing of presentation. Confirmation of diagnosis requires ultrasound imaging. Any mastitis which does not resolve within 48-72 hours of antibiotic treatment requires ultrasound imaging to rule out breast abscess.

Photo: breast abscess



Photo Source: Family Health Services, Department of Health

Galactocele is a milk retention cyst. It is lined by flattened epithelial cells and initially contains milky fluid, which becomes thicker and creamier as water is reabsorbed. The wall fibrosis surrounding the collection of milk fluid is likely a post-inflammatory response secondary to leakage of milk into the adjacent tissue, commonly as a result of blockage of a milk duct.⁶ It presents as a non-painful or slightly tender cystic breast lump. Clinical examination alone cannot be relied on to diagnose galactocele. Ultrasonography is essential to distinguish galactocele from other causes of breast masses.^2,3,6 Aspiration cytology confirms the diagnosis and excludes malignancy. Galactocele may persist for many months or reduce in size slowly. Galactocele itself does not affect milk production.

Relationship between blocked milk ducts, mastitis, breast abscess and galactocele

These four conditions are very frequently encountered in the maternal & child health centres or lactation clinics. Normally, acute blocked ducts resolve within 24-48 hours with effective milk removal. If timely and effective treatment is not provided, blocked ducts may progress to mastitis and breast abscess. A galactocele may occur as a sequel to blocked milk ducts, mastitis or abscess.¹ In the latter two conditions, the galactocele appears as a persistent breast lump after the resolution of signs of acute inflammation. The possible sequence of events can be illustrated as below:-

Non-breastfeeding related breast lumps include benign and malignant tumours which require ultrasound imaging +/- fine needle aspiration for cytology or core biopsy to confirm the diagnosis. Breast cancer during lactation is often diagnosed late as breast lumps occurring during lactation are commonly managed as breastfeeding-related conditions such as blocked ducts and mastitis. Among breastfeeding mothers and health care workers alike, there is generally a low index of suspicion that breast lumps may be malignant. Delay in seeking medical advice or providing diagnostic imaging may end up with a late stage malignancy.⁷ In sum, though breast cancer during lactation is uncommon, prompt imaging is recommended for any persistent or unresolved breast lump. Petok⁸ recommended prompt referral in the following situations:
․ A breast mass that shows no improvement within 72 hours of treatment
․ Plugged milk ducts or an area of milk stasis occurring repeatedly in the same location
․ Local symptoms and signs of mastitis unaccompanied by a fever that do not resolve after antibiotic treatment

Can galactocele be managed as “chronic” blocked ducts?

Gentle breast massage during milk removal is one of the effective ways to manage blocked ducts. However, as a milk retention cyst, a galactocele cannot be resolved by breast massage or compression.¹ Managing a galactocele as “chronic” blocked ducts with repeated breast massage not only frustrates the mother because of the unproductive outcome, it also ends up with unnecessary delay in investigation or specialist referral. Besides, forceful breast massage may induce breast discomfort, which may inhibit milk ejection reflex and reduce milk production.

For this mother, the unresolved breast lumps, particularly the physical finding of the larger breast lump with ill-defined margin plus a family history of breast cancer warrant an early specialist referral and investigation.

Recommended management of galactocele^1-3,6

Ultrasound-guided fine needle aspiration for cytology is diagnostic as well as therapeutic. In the case of a confirmed galactocele, further treatment is not required generally. Repeated needle aspiration or surgical excision is only necessary if the mother finds the galactocele troublesome. The mother can continue to breastfeed in the presence of the galactocele.


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