Milk cysts: Some visual features

The article is written by MSc, BS. Nguyen Le Thao Tram, Department of Diagnostic Imaging - Vinmec Nha Trang International General Hospital

Milk cysts form due to blockage of milk ducts causing a milk-filled cyst to accumulate in the breast tissue. This disease is very common in lactating women, especially at the time of weaning. A milk cyst is a benign lesion that usually shrinks and disappears on its own.

Milk cysts (also known as Galactocele or Lactocele) are benign breast lesions that are common in lactating women, especially at the time of weaning.
The clinical manifestation of milk cyst is a large but painless mass, without any signs of redness and heat, which is another characteristic of inflammation or breast abscess. Lesions may be single or multiple, unilateral or bilateral. The most common location of cysts is below the areola. The most common complication is a superinfected milk-coated cyst that can progress to an abscess.
Milk cysts are formed due to blockage of milk ducts causing a milk-filled cyst to accumulate in the breast tissue. After imaging facilities, we can aspirate the cyst fluid for accurate analysis in case of need. On the slide, the pathologist can see that the fluid content of the milk capsule is mainly white and viscous if a new cyst is formed or changes to a thicker fluid if it is an old cyst. The biological characteristics of the cyst fluid are mainly protein, fat and lactose.

2.1. Mammography Milk cysts present quite differently depending on the amount of protein and fat as well as the consistency of the fluid, based on these features, the milk cyst can have the following forms:
Pseudolipoma: due to contains many fatty components, blocks have photoluminescent properties. A cyst has a fat-fluid level within cyst: when fat and fluid are present together. Pseudo hamartoma: when the cyst contains old milky fluid and water. Because stale milk has a high viscosity, the mass will appear as a solid tissue on the mammogram.

2.2. Ultrasound Ultrasound images are quite variable, in general can be one of the following three main types:
Cyst or multiple cysts; Mixed mass of cysts and solids; Solid block. However, with analysis of vascular features on doppler ultrasound, there does not seem to be a perfusion signal inside the milk capsule, which is a feature that helps to distinguish solid masses from breast tumors.

Some other conditions that need differential diagnosis with milk cysts are breast abscess, fibroadenoma, fat necrosis, lactating adenoma and even breast cancer.

A milk cyst, as noted, is a benign lesion, which will usually shrink and disappear on its own. But it can still turn into a dense fluid that looks similar to a fibroadenoma (fibroma) or a complex cyst.
Treatment of cysts is mostly about letting them go away, but if they don't go well, fine-needle aspiration (FNAC) may be needed.
To protect your health, when milk cysts appear, you should immediately go to a medical facility to be examined and consulted by specialist doctors. At Vinmec International General Hospital, there is a Breast Cancer Screening Package, which helps customers screen and detect breast cancer early even when there are no symptoms. When registering for the Breast Cancer Screening Package, customers will receive:
Examination and consultation with an oncologist. Breast cancer screening by bilateral breast ultrasound and mammogram. Up to now, Vinmec has become a prestigious address in breast cancer screening with:
Team of highly qualified and experienced doctors. Comprehensive professional cooperation with domestic and international hospitals: Singapore, Japan, USA, etc. Comprehensive treatment and care for patients, multi-specialty coordination towards individualizing each patient. Having a full range of specialized facilities to diagnose the disease and stage it before treatment: Endoscopy, CT scan, PET-CT scan, MRI, histopathological diagnosis, gene-cell testing, .. There are full range of mainstream cancer treatment methods: surgery, radiation therapy, chemotherapy, stem cell transplant..

References: radiopaedia.org, breast-cancer.ca