Galactoceles, also known as lactocoeles, are benign breast lesions commonly seen in young lactating women. They mostly occur after the cessation of lactation, when milk may be retained, becoming ‘stagnant’ and causing blockage of the ducts. The term ‘galactococele’ is derived from the Greek words ‘galatea’ and ‘coele’ meaning ‘milky white’ and ‘pouch’, respectively. Galactocoeles have a predilection to form in the sub-areolar region of the breasts.
Galactoceles are caused by any kind of blockage in the ducts of the breast during or just after stopping lactation. While breast carcinomas may sometimes cause a blockage which results in a galactocele, these lesions are due to more routine and benign causes in a majority of women. A galactocele usually presents as a painless lump in the breast. These lumps form over a few weeks to months. The lesions can be uni- or bilateral, and may appear as single or multiple nodules.
Pathology
A galactocele is a retention cyst caused by lactiferous duct occlusion. They feel like ordinary cysts but they contain milk instead of just clear fluid. While they can be uncomfortable, they are not dangerous.
Percutaneous aspiration is performed in order to diagnose the lesion. The aspirated material from the cyst is subjected to biochemical analysis which shows varying amount of proteins, lactose, and fat. A galactocoele may appear white due to the milk within it. If the milk is fresh, it has the usual viscosity, but if it is older, it often appears thickened.
Treatment usually involves draining (“aspirating”) the milk using a fine needle.
Radiographic Features of Galactocoele
Mammography
On mammography, a galactocoele has various appearances, depending on the amount of protein and fat and the fluid consistency.
The high fat content causes the mass to be radiolucent, and these galactocele masses are called pseudolipomas.
With an older galactocele, the milk no longer separates into milk solids and water. Instead, the high viscosity of the milk gives rise to a hamartoma-like appearance, because of which they are called pseudohamartomas. In this case, the fluid is stickier and thicker and is in a ‘pseudo-solid’ state. This type of galactocele resembles a carcinoma more closely than other types, though the distinct margins and well-defined shape clearly suggest a benign mass.
In pregnant women, mammograms are usually not performed. Instead, ultrasound scanning can be used to study the mass in the breast.
Ultrasound
On breast ultrasound, the appearance of the cyst may vary. The usual appearances are as follows:
- Cystic / multicystic: ~50%
- Mixed (cystic + solid): ~37%
- Solid: ~13%
Galactoceles typically appear as small, round hypoechoic nodules in a sonogram. They usually have well-defined margins with thin walls, but may rarely appear to have indistinct or microlobulated margins. Mammographic and ultrasound findings may be confusing to the radiologist who is trying to investigate a cyst or mass in the breast.
Doppler & Histological Analysis
On color Doppler investigation, lack of blood flow is evident. On histological analysis, galactoceles often show the presence of inflammatory fluids or necrotic debris. Inflammation in the cysts is usually caused by leakage. Secondary infection resulting in a breast abscess is a complication associated with galactoceles.
Treatment and Prognosis
Galactoceles usually resolve quickly on their own in most cases, as the hormonal changes linked to lactation settle down. Very few patients have residual masses which may be mistaken for a carcinoma or a fibroadenoma. On mammogram and ultrasound, the features of the pseudohamartoma may resemble those of a hamartoma or possibly a complicated cyst.
References
Further Reading
New position statement highlights importance of breastfeeding in emergencies