This page was reviewed under our medical and editorial policy by
Daniel Liu, MD, Plastic and Reconstructive Surgeon.
This page was reviewed on February 8, 2022.
After breast cancer surgery, fluid may collect where tissue was removed. This swelling is called a seroma. It may resolve on its own over time, or it may need to be drained. Seromas may be uncomfortable and lengthen your recovery time, but they aren’t cancerous.
Seromas are the most common complication of breast cancer surgery. Serous fluid, the clear portion of blood (serum), and lymphatic fluid may build up under the skin in the spaces where tumors, surrounding tissue and axillary lymph nodes were cut out. Seromas may also form in the abdominal region if tissue is taken from there for use in breast reconstruction.
Why seromas develop isn’t clear. Suspected factors include:
According to research published in the Journal of Breast Cancer and Molecular and Clinical Oncology:
To a lesser extent, inadequate pain relief and use of neoadjuvant chemotherapy have been associated with seromas.
Heavier body weight and higher body mass index are probable risk factors, and perhaps high blood pressure (hypertension). But no confirmed association with seromas following breast cancer surgery has been found regarding:
Seromas may form after either a lumpectomy or mastectomy, as well as following the removal of neighboring lymph nodes, breast reconstruction, and other types of surgery. They may take weeks or months to resolve.
It’s theorized your body responds to the trauma of surgery by releasing serous fluid that probably comes from the lymphatic system. Other health experts say the fluid in a seroma represents a mix of lymph and serum.
During surgery, doctors may place tubes in your wound to drain off excess fluid. Seromas often result after these drains have been taken out. Although your body generally tends to reabsorb this fluid, sometimes your doctor may need to drain it with a hypodermic needle or replace a drainage tube.
Symptoms that signal seroma drainage may need to be done include:
Alert your care team if you’re experiencing any of these symptoms.
Small seromas often disappear over time, but long-lasting ones can be troublesome. If your seroma cannot be easily felt through the skin, its dimensions may be determined through ultrasound or a computed tomography (CT) scan.
The fluid in persistent or large seromas may be removed with a hypodermic needle (in a procedure called aspiration), but the fluid may recur. Repeated aspirations raise the risk of infection.
To resolve persistent seromas, your doctor may inject an irritant into the cavity that was formed by tissue removal. This procedure, called sclerotherapy, aims to promote healing by closing up the empty space. Recurrent seromas may require replacement of a drainage tube or, less commonly, surgical drainage.
Other seroma treatments are preventive, and may include:
Techniques used during a mastectomy and lymph node removal that reduce the empty or dead space formed by tissue loss are thought to help lower the risk of developing a seroma.
Steroids are sometimes used to reduce the inflammatory response to surgery that’s thought to lead to seromas. Research in the World Journal of Surgical Oncology notes that putting steroids into the surgical wound after breast reconstruction or the first day after a mastectomy with sentinel lymph node biopsy has been shown to cut the risk of seroma development, but a dose of steroids before mastectomy or after mastectomy with axillary lymph node removal didn’t seem to change the odds. The use of steroids may also raise the risk of bacterial infection of seromas.
Potential complications may include: