Cyclical pain, swelling or bleeding from a scar, belly button or abdominal wall lump should be checked.

Endometriosis can sometimes affect the abdominal wall, belly button or surgical scars, including C-section scars, laparoscopy scars or other abdominal surgery sites. These symptoms may be missed if endometriosis is thought of only as pelvic pain or painful periods. Not every scar lump or belly button change is endometriosis, but a changing, painful or bleeding area should be assessed properly.

What this can involve

Scar or abdominal wall endometriosis means endometriosis-like tissue is found in or near the skin, scar tissue, muscle or abdominal wall. It may appear:

  • in or near a C-section scar
  • in or near a laparoscopy scar
  • around the belly button
  • in the abdominal wall muscle
  • near another previous abdominal or pelvic surgery site

Endometriosis in these areas may occur after surgery, but belly button endometriosis can also occur without previous surgery.

Symptoms to look out for

Symptoms may include:

  • a painful lump
  • swelling
  • tenderness
  • colour change, such as blue, purple, brown or darker skin
  • bleeding from the belly button or scar
  • discharge
  • itching or irritation
  • pulling or burning pain
  • pain that worsens before or during a period
  • a lump that changes size or sensitivity with the cycle

The monthly pattern is important. A lump or scar that becomes painful, swollen or bleeds around the menstrual cycle should be mentioned clearly to a healthcare professional.

Why history matters

Tell your clinician about any previous surgery, including:

  • C-section
  • laparoscopy
  • hysterectomy
  • appendectomy
  • hernia repair
  • abdominal surgery
  • pelvic surgery
  • surgery around the belly button

Also explain when symptoms started. Scar endometriosis symptoms may appear months or years after surgery, so older surgery can still be relevant.

Assessment

A changing lump, bleeding scar, painful belly button or abdominal wall swelling should be assessed. Assessment may include:

  • medical history
  • examination of the lump or scar
  • review of cycle pattern
  • ultrasound
  • MRI or CT in selected cases
  • referral to gynaecology, dermatology, general surgery or an endometriosis specialist
  • biopsy or removal with histology where appropriate

Because other conditions can look similar, assessment should not rely on appearance alone.

Treatment planning

Treatment depends on the location, size, symptoms, imaging findings and whether pelvic or extra-pelvic endometriosis is also suspected. Options may include:

  • monitoring in selected cases
  • symptom management while awaiting assessment
  • surgical removal where appropriate
  • histology to confirm the diagnosis
  • wider endometriosis review if other symptoms are present

If surgery is discussed, ask whether the full area will be removed, whether margins matter, whether muscle or deeper tissue is involved, and whether tissue will be sent for histology.

Questions to ask

You may want to ask:

  • Could scar, belly button or abdominal wall endometriosis be possible?
  • Could this be linked to previous surgery?
  • What imaging is suitable?
  • Does the lump involve skin, scar tissue, muscle or deeper tissue?
  • Should this be reviewed by an endometriosis specialist, dermatologist or surgeon?
  • Will tissue be sent for histology if it is removed?
  • Should I also be assessed for pelvic or extra-pelvic endometriosis?
  • What symptoms should I treat as urgent?

Prepare before you speak with a healthcare professional

Use our Prepare for Appointment Tool to organise your symptoms, questions, previous surgery history, photos, cycle pattern and priorities before your appointment. Try to record:

  • where the lump or painful area is
  • when it first appeared
  • whether it changes with your cycle
  • whether it bleeds or leaks fluid
  • whether it changes colour
  • whether it is growing
  • whether you have pelvic, bowel, bladder, chest or nerve-like symptoms too
  • what surgery you have had and when

Photos taken at different points in your cycle may also help show changes.

Finding the right type of care

Use the Endometriosis Care Directory to explore different types of endometriosis-related care providers. The directory is for research and information only. It is not a recommendation, referral service, ranking or medical advice. Always check details directly with the provider and speak with an appropriate healthcare professional before making decisions about your care.

Final reminder

Pain, swelling or bleeding from a scar, belly button or abdominal wall area should not be ignored, especially if it follows a monthly pattern. You deserve proper assessment, clear explanations and care that considers both the local lump and the wider endometriosis picture. This resource is here to support your understanding, not replace medical advice from a qualified healthcare professional.