A galactocele is also known as a milk cyst which is a clogged milk duct commonly associated with childbirth, in both breast feeding and non-breast feeding mothers. The milk inside of the cyst is hard and it usually does not become infected.

These simple milk-filled cysts probably form from blockage of a lactiferous duct (milk duct). They are are usually firm and painless bumps in the breast tissue, usually in the upper outer areas beyond the edge of the areola or directly beneath the areola.

Galactocele and other breast lumps

Galactoceles are similar to other types of cysts but instead of clear fluid, they contain milk. These small lumps are not dangerous, though they can be uncomfortable. Medical treatment involves a physician draining the milk cyst with a fine needle.

Many doctors will order an ultrasound and a fine needle aspiration biopsy just to be sure that the lump is harmless. The presence of milk aspirated from the mass and not clear fluids or blood will most likely confirm the diagnosis and rule out cancer and fibroadenoma. Aspirated milk tends to be thick when the lesion is older and the sample is from after breast feeding has stopped.

A milk-filled breast cyst can mimic fibroadenomas and breast carcinomas, but they are always benign and do not increase risk of breast cancer in any way. A cyst can be caused by anything that blocks a breast duct during breastfeeding. While breast carcinoma can technically cause a change and blockage of some kind, it's much more likely that it's the result of ordinary, benign causes. Milk cysts are the most common non-cancerous breast lesions in lactating women. They seem to occur more often after breastfeeding has stopped and due to milk being retained and stagnant within the breast ducts.