Hard Lumps Under the Armpit: Causes and Concerns

There is a hard lump in the armpit?

In the past six months, I have noticed a lump in my left armpit.
It is not visible from the outside, and it does not hurt unless I press on it.
The lump feels hard and does not move.
It does not seem to be getting larger, and it is about the size of a peanut.
I have researched a lot but am uncertain about what this condition might be, so I would like to consult you.
Thank you, doctor.

Ms. Wu, 20~29 year old female. Ask Date: 2023/09/07

Dr. Chen Sirong reply Oncology

Ms.
Wu / 20 years old / Female
1.
If there is no growth over six months, the chance of it being benign is higher.

2.
Researching a lot of information is not as effective as directly visiting a doctor at the hospital.

3.
It's advisable to consult in person; online consultations cannot provide the comprehensive assessment that includes observation, inquiry, and examination.
Even if they suggest a higher likelihood of being benign, it should only be taken as a reference.

Taoyuan Hospital, Dr.
Chen Sih-Rong

Reply Date: 2023/09/07

More Info

The presence of hard lumps under the armpit can be concerning, and it’s important to understand the potential causes and when to seek medical attention. Based on your description, the lump you’ve noticed is approximately the size of a peanut, hard, and painful when pressed, but it hasn’t changed in size over the past six months. Here are some possible explanations for this condition:
1. Lymphadenopathy: One of the most common causes of lumps in the armpit area is swollen lymph nodes. Lymph nodes can become enlarged due to infections (like a cold or flu), inflammatory conditions, or even malignancies. If the lump is tender and painful, it may indicate an active infection or inflammation.

2. Lipoma: A lipoma is a benign tumor made up of fat tissue. These are usually soft, movable, and painless, but in some cases, they can feel firmer and may cause discomfort if they press against surrounding tissues.

3. Cysts: Sebaceous cysts or epidermoid cysts can develop under the skin and may feel firm. They are typically benign and can become painful if they become inflamed or infected.

4. Fibroadenoma: While more common in breast tissue, fibroadenomas can occasionally present in the axillary region. They are benign tumors that are usually painless and movable.

5. Infections: Conditions such as abscesses or infections in the skin or deeper tissues can lead to painful lumps. These may require drainage or antibiotics.

6. Malignancy: Although less common, hard lumps that are fixed, painful, or have changed in size or shape could be indicative of a more serious condition, such as lymphoma or breast cancer.
Given that the lump is painful when pressed, it’s advisable to consult a healthcare professional for a thorough evaluation. They may perform a physical examination and could recommend imaging studies, such as an ultrasound, to better understand the nature of the lump. In some cases, a biopsy may be necessary to rule out malignancy.

When to Seek Medical Attention
- If the lump increases in size or changes in shape.

- If you experience additional symptoms such as fever, night sweats, unexplained weight loss, or persistent pain.

- If the lump becomes red, warm, or increasingly painful, which may indicate an infection.

Conclusion
While many lumps under the armpit are benign and not a cause for concern, it is crucial to have any new or changing lumps evaluated by a healthcare provider. Early diagnosis and treatment can help address any underlying issues and provide peace of mind. If you have any further questions or concerns, please do not hesitate to reach out to a medical professional for personalized advice.

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