Why does a lump in the armpit get dismissed?
Most swollen lymph nodes in the armpit are harmless. They often swell for a short time as the body fights something off, then shrink back.
Common harmless causes of swollen lymph nodes in the armpit include:
- An infection in the arm, hand, or breast skin.
- Small cuts or ingrown hairs from shaving.
- A recent vaccine in the same arm, such as a COVID or flu shot.
Vaccine swelling became much more familiar during the COVID years. A node that swells after a shot in the same arm is common and usually goes down within weeks. So a doctor who hears “lump under my arm” often has a ready answer.
That answer is usually right. But breast cancer often spreads first to the lymph nodes in the armpit. Sometimes a swollen node is the first thing a woman notices. Other cancers, such as lymphoma, a cancer of the immune system, can also start there. A node that does not act like a harmless one needs a closer look.
Contact Us for a Free, Confidential Consultation
Article written by Gregory Unatin, Esq. Greg is a managing partner in the law firm of Lupetin & Unatin, a medical malpractice law firm located in Pittsburgh and serving Western Pennsylvania.
Our practice is limited to high-value catastrophic cases because that is where we can do the most for our clients and for patient safety.
The following is a hypothetical situation designed to demonstrate a common form of medical error. It is not a real case, and no physician has reviewed it or offered an opinion about it.
Rachel is 49 and lives near Erie, PA. In October, she gets a flu shot and a COVID booster in her left arm. Two weeks later, she feels a lump in her left armpit. Her nurse practitioner says it is a lymph node, a small gland that filters fluid. She says the vaccines likely caused it and it should go away.
In January, the lump is still there and feels harder. She is told the same thing. In April, she notices a dimple in the skin of her left breast. A mammogram, an ultrasound, and a biopsy follow. A biopsy removes a small piece of tissue for testing. It shows breast cancer in the breast and the node.
Rachel wonders whether those months mattered to her treatment or prognosis. This article can help you sort out when an armpit lump should be checked, and when a delay may support a claim.
When is a lump in the armpit a sign of breast cancer?
Usually, a lump in the armpit is not cancer. But it can be a sign of breast cancer, especially when it lasts beyond several weeks or keeps growing. A node that feels hard or fixed, or that comes with a breast change, also needs a closer look.
These are the features that usually call for imaging:
- A node that lasts beyond several weeks, even after a vaccine or infection has had time to settle.
- A node that keeps growing.
- A node that feels hard, or does not move under the skin.
- A node on the same side as a breast lump, skin change, or nipple change.
- A node with no clear cause, such as no recent shot or infection.
The Society of Breast Imaging, a national group of breast imaging doctors, issued guidance on swollen nodes after vaccines in 2022. In general, if a palpable lump appears after a vaccine, watchful waiting or clinical recheck for a few weeks is reasonable; however, if the node is hard, fixed, progressively growing, or accompanied by any breast finding, or if it persists well beyond the expected initial reactive period without shrinking, it must not simply be dismissed indefinitely as “vaccine swelling”. Doctors should also ask which arm got the shot. A node on the other side has no vaccine to explain it.
Imaging for an armpit lump usually starts with an ultrasound, which uses sound waves to make a picture. It is often paired with a diagnostic mammogram, which is aimed at the problem area. The mammogram looks for a cancer in the breast that may have spread to the node. The American College of Radiology, a national group of imaging doctors, addresses this workup in its guidance. According to the American College of Radiology (ACR) Appropriateness Criteria® Imaging of the Axilla (2021/2022), a new, palpable, unilateral armpit lump should be evaluated with a targeted axillary ultrasound and paired diagnostic mammogram to rule out breast cancer.
If the node looks suspicious, the next step is usually a needle biopsy. A thin needle takes a small sample of tissue for testing.
A careful doctor also examines both breasts when a woman reports an armpit lump. The node may be a clue to something abnormal in the breast.
Where does the chance to find it earlier get missed?
- The node was blamed on a vaccine, and no one rechecked it. Attributing the enlarged node to a vaccine may have been fair, at first. But months later, the same answer was given without any imaging.
- The node was treated as an infection with no follow up. You got antibiotics, but no one set a date to make sure the node went down.
- No one examined your breast. The visit focused on the armpit. A breast lump or skin change on the same side went unnoticed.
- A hard or growing node was called normal. The chart may describe a firm or enlarged node with no plan.
- Imaging was ordered but the result was not acted on. An ultrasound report suggested a biopsy or recheck, and it never happened.
What should I check in my own records?
You can answer most of these from memory, your patient portal, or your records.
- When did you first notice the lump, and when did you report it?
- Had you had a vaccine in that arm? On what date?
- Did any note describe the node’s size, or say it felt hard or fixed?
- Did anyone examine your breasts at that visit?
- Was an ultrasound or mammogram ordered? Was it done?
- Did anyone set a date to recheck the node?
- How much time passed between your first report and your biopsy?
Did the delay change the outcome?
A missed step alone is not enough for a claim. The question is whether earlier testing would likely have found the cancer at an earlier, more treatable stage.
This fact pattern has a twist. If the swollen node was cancer when you first reported it, the cancer had already reached the lymph nodes. The key question is often whether it spread further during the delay. That could mean more nodes, or distant organs.
Breast cancers grow at different speeds. Some grow slowly over years. Others grow fast. A delay of a few months may matter a great deal for one woman and very little for another.
Medical malpractice lawyers and the experts they consult to review a case focus on a few things. They compare the size of the node and any breast tumor at the missed chance to their size at diagnosis. They count how many nodes were involved and check for spread to other organs. They look at the type of cancer and how fast that type tends to grow. And they measure the time between the missed chance and the diagnosis.
A delay can also change treatment. It may mean a larger surgery in the armpit, more chemotherapy, which means strong cancer drugs, or a mastectomy, which removes the whole breast.
In Pennsylvania, a family does not always have to prove that an earlier diagnosis would have saved her. It can be enough to show that the delay meaningfully raised the risk of harm. That added risk must also have played a real part in what happened.
When is a missed armpit lump not medical malpractice?
Not every delay is malpractice. A bad outcome does not prove someone made a mistake.
- The node followed a recent vaccine and was rechecked. A doctor who linked a node to a shot in the same arm and set a recheck date was likely acting reasonably.
- The node went away. If it shrank and later a new problem appeared, the first doctor may not have missed anything.
- The workup was done and read correctly. Some cancers do not show on a mammogram or ultrasound, even when the test is done and read well. A doctor who did the right workup is not at fault just because the cancer was found later.
- The delay likely made no difference to prognosis or treatment. The cancer may have already spread to distant organs when the node was first reported.
What harms matter in these cases?
Our firm focuses on delays that led to death or catastrophic injury. In breast cancer cases, these are the harms that usually matter:
- Cancer that spread to distant organs, such as the bones, liver, lungs, or brain, before it was found. It can still be treated, but it can no longer be cured.
- Death from a breast cancer that, if found earlier, would likely have been curable.
What to expect when you contact our office
Before we take a case, we review the records and imaging with medical experts. Pennsylvania requires a medical professional’s written statement that a claim has merit before a case can go forward. That review also helps answer whether the delay changed the outcome. A doctor, a nurse practitioner, a practice group, an urgent care center, or a hospital system may each have played a role.
Pennsylvania has filing deadlines. For a living patient, the deadline is generally two years from a key date. That is when she knew, or should have known, that she was harmed and that medical care may have caused it. In delayed diagnosis cases, that date is often near the cancer diagnosis. After a death, claims generally must be filed within two years of the date of death. Learn more about how long you have to file a medical malpractice in Pennsylvania. For additional information on breast cancer misdiagnosis, see our main article on delayed diagnosis of breast cancer.
Frequently Asked Questions
Yes. A COVID or flu shot can cause a swollen node in the armpit on the same side. It usually goes down within weeks.
When it lasts beyond several weeks, keeps growing, feels hard or fixed, or comes with a breast change.
Usually an ultrasound, often with a diagnostic mammogram. A needle biopsy follows if the node looks suspicious.
No. A claim needs a skipped step and proof that the delay likely changed the outcome or raised the risk of harm.
Free Consultation — No Fee Unless We Win
Lupetin & Unatin, LLC represents Pennsylvania patients harmed by physicians who failed to meet the standard of care.