A Surgeon’s Thought on Soft Tissue Mass: What Patients Should Know

October 27, 2026

Dr. Matthew J. Finnegan is a robotic general and colorectal surgeon with Shore Physicians Group in Somers Point. His surgical team operates at Shore Medical Center.

A soft tissue mass is a lump or growth that develops in tissues such as fat, muscle, tendons, nerves, blood vessels, or connective tissue. Most soft tissue masses are benign, but some need prompt evaluation to rule out infection, bleeding, or a rare cancer called soft tissue sarcoma.

Key takeaways

• Many lumps are harmless, but any new or changing mass should be evaluated by a health care professional.
• Concerning features include a lump that is growing, deep, firm, larger than about a golf ball, painful, or associated with numbness, weakness, swelling, fever, unexplained weight loss, or skin changes.
• Do not assume a painless lump is harmless. Soft tissue sarcomas are often painless at first.
• If sarcoma is possible, imaging and biopsy should be planned carefully, ideally by a team experienced with soft tissue tumors.

When to seek medical evaluation

Make an appointment if you notice a new lump or swelling, especially if it is enlarging over days, weeks, or months; is deep under the skin; is about the size of a golf ball or larger; does not move easily; causes pain, tingling, numbness, or weakness; or returns after removal. Seek urgent care for rapidly worsening pain, fever, redness spreading around the lump, sudden swelling after injury, or symptoms such as trouble breathing or severe abdominal pain.

Common causes

• Lipoma: a common benign fatty lump, often soft and movable.
• Cyst: a fluid- or debris-filled sac under the skin.
• Hematoma: a collection of blood after injury or blood thinner use.
• Abscess or infection: may be tender, warm, red, or associated with fever.
• Benign nerve, tendon, or muscle tumors: may cause pressure symptoms depending on location.
• Soft tissue sarcoma: a rare cancer that can arise in fat, muscle, blood vessels, nerves, tendons, or connective tissue.

How a soft tissue mass is evaluated

1. History and physical exam: Your clinician will ask when the lump appeared, whether it is changing, whether it hurts, and whether there was an injury or infection.
2. Imaging: Ultrasound may be used for small superficial lumps. MRI is often preferred for larger or deeper masses. CT may be used for masses in the chest, abdomen, pelvis, or when MRI is not appropriate.
3. Biopsy: If imaging raises concern, a sample of tissue may be removed for diagnosis. For suspected sarcoma, biopsy planning matters because the biopsy path can affect later surgery.
4. Specialist referral: A surgeon, orthopedic oncologist, surgical oncologist, radiologist, pathologist, medical oncologist, or radiation oncologist may be involved depending on the findings.

Treatment options

Treatment depends on the diagnosis, size, depth, location, symptoms, and whether the mass is benign or malignant. Some benign masses can be observed if they are not changing or causing symptoms. Others may be removed if they are painful, growing, bothersome, or uncertain in diagnosis. If cancer is found, treatment may include surgery, radiation therapy, chemotherapy, targeted therapy, or a combination, guided by a multidisciplinary team.

How to prepare for your appointment

• Write down when you first noticed the mass and whether it has changed.
• Take a photo or measure the lump if it is visible, and note changes over time.
• Bring a list of medications, including blood thinners and supplements.
• Mention prior cancer treatment, radiation therapy, significant injuries, infections, or family history of rare tumor syndromes.
• Bring copies of prior imaging reports or biopsy results if available.
  

Questions to ask your care team

• What are the most likely causes of this mass?
• Do I need imaging, and which type is best?
• Should I see a specialist before any biopsy or removal?
• If a biopsy is needed, who should perform it?
• What symptoms should prompt urgent care?
• If this is benign, should it be monitored or removed?
• If this is cancer, what type is it, what stage is it, and what treatment options are recommended?

Bottom line

Most soft tissue masses are not cancer, but the safest approach is to have new, enlarging, deep, firm, painful, or larger masses checked. Early evaluation helps avoid delays and ensures that imaging, biopsy, and treatment are done in the right order.

To schedule an appointment with Matthew J. Finnegan, MD, Robotic General & Colorectal Surgeon with Shore Physicians Group, call 609-365-6239. Dr. Finnegan treats patients age 18 and older at 649 Shore Road, Somers Point.