Breast Cancer: Seroma in the Armpit

Updated November 21, 2016

Any surgery comes with some risk, and potential for complication. This is especially true when tissue has to be removed. One of the most common treatments of breast cancer is a mastectomy, or removal of the mammary glands and surrounding breast tissue. According to the World Journal of Surgical Oncology, the most common surgical complication in women who have undergone this surgery is the development of a seroma in the area under the arm.


The suffix "-oma," in medicine, means "a gathering or pooling of". A seroma is a soft tissue tumour, or build-up of serous fluids, which pool under the skin. Serous fluids are the yellow to clear fluid produced by the lymphatic system. It is the same fluid that pools inside blisters. After breast cancer, these fluids tend to pool in the armpit, in the area where tissue was removed during the mastectomy.


According to Dr. Gordon Cameron, when the lymph glands in the armpit are removed, the tiny tubes that hook the glands together are severed. This lets serous fluid escape into the area below the skin. A mastectomy leaves an open space where the breast tissue is removed, and serous fluid runs into this empty space, causing a seroma. Some studies also suggest that early removal of the surgical site's draining tube may be linked to formation of a seroma.


There are two primary symptoms of seroma formation. The first is bulging of the surgical site. The second is fluid-like movement of the skin over the seroma. Essentially the site will both look and feel like a waterbed bladder, or water balloon. Seromas typically form between seven and 10 days after surgery, and just after the drainage tube is removed.


The presence of a seroma is detected by palpation, or feeling the area affected. A doctor may also use a syringe to draw fluid out of the mass, and have it tested. This will ensure that it is just serous fluid collecting, and not a more serious problem. It will also allow the doctor to check for infection.


Though seromas are typically only a minor complication, there are symptoms that may be indicative of a more serious problem, and experiencing these symptoms is reason to call your doctor immediately. Call your doctor if you feel increasing pressure on the healing area of your surgical site, or if the amount of fluid seems to be dramatically increasing. Also, if the site of the seroma becomes red, warm or sore to the touch, these could be signs of infection, and your doctor should check it out. Finally, if the swelling at the surgical site is increasing, call your doctor; this could be a sign of Lymphodema rather than seroma.


If the bulging becomes significant and uncomfortable, your doctor may use a needle and syringe to extract fluid from the armpit. In most cases, however, the body will reabsorb the serous fluid on its own over time, and no treatment is necessary. Typically these fluids are reabsorbed and the seroma disappears in about a month, but the healing process can take up to a year.

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About the Author

Misty Barton has been working in the fields of composition and journalism for over 10 years. She has a Bachelor of Science in English education and a Master of Arts in English and composition. She has written for various online publications including a blog that specifically addresses the concerns of work-at-home mothers.