Medical Oncologist
CION Cancer Clinics
Fluid collecting under the wound: seroma | CION Cancer Clinics
A seroma is a pocket of clear, straw-coloured fluid that gathers under the skin where tissue or lymph nodes were removed. Many small ones go away on their own over some weeks. A large, tight or painful seroma is usually drained with a needle in the clinic, sometimes more than once. This page explains what it feels like, how it is treated, and when it needs to be seen quickly. CION Cancer Clinics’ surgical oncologists in Hyderabad can talk this through with you.
MM
Medically reviewed by Dr. Muralidhar MuddusettyConsultant Surgical Oncologist · MBBS (AIIMS), MS (Surgery, AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh) · last reviewed September 2026, next review due September 2027
17+specialists on panel
15,000+patients treated
35+centres across Telangana & AP
4.8★ / 800+Google rating
On this page
- What is a seroma, and does it need treatment?
- What does a seroma look and feel like?
- How is a seroma usually treated?
- What happens when a seroma is drained?
- Is it a seroma or something else?
- Who is more likely to get one, and can you prevent it?
- What do people often get wrong about seromas?
- Common questions about seroma after surgery
The short answer
What is a seroma, and does it need treatment?
A seroma is a pocket of clear, straw-coloured fluid that collects under the skin where tissue was removed. Many small ones go away on their own over some weeks. A large, tight or painful one is usually drained with a needle in the clinic.
Why it forms
When a surgeon removes a tumour or lymph nodes, a space is left behind. The body fills that space with the watery part of blood and lymph, the clear fluid that normally drains through the lymph nodes. Drains placed during the operation carry this away at first. A seroma often appears in the days after the drain comes out.
Where it is most common
It is most often seen after breast surgery, especially when lymph nodes are removed from the armpit. It also happens after groin lymph node surgery, large operations on the tummy wall, and removal of lumps from the back, thigh or neck.
What this page cannot tell you
It cannot tell you whether your swelling is a seroma. Blood, pus or a hernia can look similar from the outside. The team may need to examine it, or look with an ultrasound, before they can say.
A seroma is a healing problem. It does not mean the cancer has come back.Recognising it
What does a seroma look and feel like?
Most people notice it within the first couple of weeks after surgery, often soon after going home.
A soft swelling
A smooth, rounded bulge near the scar or under the arm. It often feels like a water balloon under the skin and may move slightly when you press it.
A sloshing or heavy feeling
Some people feel fluid shift when they move, or a heaviness in the chest wall or armpit. It can make the arm or clothing feel tight.
Tightness and discomfort
A small seroma is often only mildly uncomfortable. A large one can stretch the skin and ache, especially at the end of the day.
Clear fluid leaking
Sometimes the fluid seeps out of the scar or the old drain hole. Clear or pale yellow fluid is typical.
Call the team the same day if
- The skin over it turns red and hot
- The fluid becomes cloudy or smells
- You develop a fever or shivers
Not sure whether this applies to you?
Ask an oncologistTreatment
How is a seroma usually treated?
-
Watching and waiting
A small seroma that is not painful or tight is often left alone. The body slowly soaks the fluid back up. Draining a small one can sometimes make it come back faster, so waiting is a real choice.
-
Draining with a needle
If it is large, tight or painful, the fluid is drawn off with a needle and syringe in the clinic. This is called aspiration. It usually gives quick relief.
-
Repeat drainage
A seroma often refills, so it may need draining more than once. Each time there is usually less fluid, until it stops coming back.
-
A drain or a small procedure
If a seroma keeps coming back over a long time, the surgeon may place a small drain for a while, or discuss a procedure to close the space. This is uncommon.
In the clinic
What happens when a seroma is drained?
Checking the swelling
The doctor or nurse feels the area and may use an ultrasound to find the pocket of fluid and check how deep it sits.
Cleaning the skin
The skin is cleaned with antiseptic. The area near a scar is often numb after surgery, so many people feel only pressure.
Drawing off the fluid
A fine needle goes into the pocket and the fluid is drawn into a syringe. It takes a few minutes. If the fluid looks cloudy, a sample is sent to check for infection.
A dressing and advice
A small plaster goes on the needle mark. You may be asked to wear a supportive bra or a firm garment, and told when to come back.
Leave a number, we will call you
One field. No form to fill in, and no charge for the call.
Telling them apart
Is it a seroma or something else?
What you notice
What it more often is
Soft, smooth swelling, skin normal colour, fluid feel
A seroma
Firm swelling with dark blue or purple bruising
A haematoma, which is a collection of blood
Hot, red, very tender swelling with fever
An infected collection, which needs to be seen the same day
A bulge on the tummy that grows when you cough or stand
A hernia at the scar, which your surgeon should check
Risk and prevention
Who is more likely to get one, and can you prevent it?
Seromas are more likely after operations that leave a large space, such as removing the breast or many lymph nodes. Being overweight, and having a lot of fluid through the drains in the first days, also raise the chance.
What surgeons do about it
Surgeons use drains, and sometimes stitch the layers down to close the space. Studies on which method works best are mixed, and no method stops every seroma. Ask your surgeon what they plan for your operation.
What you can do
Follow the arm and shoulder exercises the physiotherapist gives you, at the pace they give them. Wear a supportive garment if one is advised. Look after the drain carefully while it is in, and write down the amount of fluid if you are asked to.
Who this advice does not fit
If you had reconstruction with an implant or a tissue flap, the plan for any fluid is different. Do not let anyone drain it outside your own surgical team.
Commonly believed
What do people often get wrong about seromas?
"The lump means the cancer is back."
A soft swelling near a fresh scar is very rarely the cancer. It is almost always fluid from healing. Still, show any new lump to your team, so they can confirm what it is.
"It must be drained, or it will turn into pus."
Most small seromas go away without any needle. Each drainage carries a small risk of letting germs in. The team drains it when it is causing trouble, not just because it is there.
"We should stop moving the arm completely until it goes."
Keeping the arm still for too long can leave the shoulder stiff. Gentle exercises, done as the physiotherapist advised, are usually still important. Ask before changing them.
"A local doctor can just drain it nearby."
It is safer to have it drained by the team that did the operation, or one they have spoken to. They know what is under the skin, especially if there is an implant.
Questions we are asked
Common questions about seroma after surgery
How long does a seroma take to go away?
It varies a lot. Small ones often settle over a few weeks. Larger ones may need draining several times and can take a few months to stop refilling. Your team will tell you what to expect for your operation, and when a seroma that keeps returning needs a different plan.
Does draining a seroma hurt?
Most people find it much less uncomfortable than they expected. The skin near a scar is often numb after surgery, so you may feel pressure more than pain. Many people feel relief as soon as the tightness goes. Tell the nurse if it hurts, and they will stop or slow down.
The seroma came back after it was drained. Is that bad?
No. Refilling is very common and expected. The space under the skin takes time to seal. Each time, there is usually less fluid. Call the team if it comes back quickly and tight, or if it turns red and hot, which could mean infection.
Can I drain it at home or press the fluid out?
No. Pressing or pricking it can let germs in and cause an infection. If fluid is leaking on its own, cover it with a clean pad and let the team know. Only a doctor or nurse should put a needle into a seroma.
Will a seroma delay radiotherapy or chemotherapy?
A small seroma usually does not. A large or infected one may, because the area needs to settle before radiotherapy planning, or infection needs treating first. Your oncologist and surgeon will talk to each other about the timing.
Can I exercise my arm with a seroma under it?
Usually yes, with the gentle exercises you were given. Stopping all movement can leave the shoulder stiff for a long time. Avoid heavy lifting and hard pushing until the team says you can. If a particular exercise makes the swelling much worse, ask the physiotherapist to adjust it.
Is the fluid a sign of infection?
Clear or pale yellow fluid is not. A seroma becomes a worry when the skin over it turns red and hot, the fluid is cloudy or smells, or you feel feverish. In that case call the team the same day, because an infected seroma needs to be looked at quickly.
Will a seroma leave a permanent lump?
Usually not. Most go away fully. Occasionally a long-lasting seroma leaves a firm area under the skin, as a lining forms around the pocket. If that happens and it bothers you, your surgeon can talk to you about the options.
Meet the Specialists
17+ senior cancer specialists. One panel for your case.
Trained at AIIMS, Tata Memorial, and leading international centres. Combined 150+ years of experience. Every complex case is reviewed by 3+ of them — together.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
Surgical Oncologist
Surgical Oncologist
Dr. Vinay Mamidala
MBBS, MS(General Surgery), M.Ch(Surgical Oncology), FMAS, FARIS(Ongoing)
Surgical Oncologist
Radiation Oncologist
Radiation Oncologist
Radiation Oncologist
Hematologist
Surgical Oncologist
Dr. Vajja Sandeep Kumar
MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology
Surgical Oncologist
Want a specific doctor for your case? Mention them when booking.
Book Free ConsultationBook an appointment with our specialist
Share your name and number — we'll call you back within 30 minutes to schedule your consultation.
Sources
- Cancer Research UK — Surgery for cancer
- Macmillan Cancer Support — Surgery
- National Cancer Institute — Surgery to treat cancer
- American Cancer Society — Cancer surgery
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Blood Collection Under the Wound (Haematoma)A swelling that is blood, not clear fluidSigns Your Wound Is InfectedWhen a swelling turns red, hot and tenderDrains, Tubes, Lines and CathetersLooking after the drain that carries fluid awayBreast cancer guideWhere seromas are most common, after breast and armpit surgery
Talk to us
Noticed a swelling near the scar?
Call the helpline with your discharge summary. We will help you reach the surgical team and work out how soon it needs to be seen. One helpline serves every CION centre.