Quick answer
A painful lump or nodule on a caesarean scar, with pain that gets worse during your period, suggests parietal endometriosis: endometrial tissue implanted in the scar, which can be treated by cryoablation without surgery.
A characteristic symptom: cyclical pain
The appearance of a painful lump or nodule on a caesarean scar, with pain that gets worse specifically during your period, is a sign suggestive of parietal endometriosis: the implantation of endometrial tissue in the scar.
It is not systematic
Not every lump on a caesarean scar is endometriosis: a granuloma, cyst, incisional hernia or other post-operative complication can look similar. It is the cyclical nature of the pain that points towards endometriosis, and MRI that confirms the diagnosis.
Which tests are needed?
An MRI of the abdominal wall is the reference test to confirm the diagnosis, determine the size and depth of the nodule, and plan any treatment.
❓ Frequently asked questions
Does scar endometriosis always need surgery?
How long after the caesarean section can this symptom appear?
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✓ Why this page is trustworthy
Written by the Interventional Radiology team at Cochin Hospital AP-HP, Université Paris Cité. Medically reviewed by an interventional radiologist of the department. Last updated: August 2026.