But if active endometriosis becomes trapped beneath adhesions, enormous pain and pressure can result. Then degeneration and destruction of the localized blood can create a cystic mass called an endometrioma. They can also grow very large. I have seen endometriomas the size of a softball. Invasion of nearby structures including the bowel, bladder and ureters can occur.
Advanced endometriosis can result in pelvises frozen with adhesions.
This means that organs designed to float freely within the pelvis are stuck together. This question has no universal answer. I have cared for advanced-stage patients who had no pain, and I have cared for patients with minimal disease who were incapacitated by pain. I have seen every degree of misery between those points. Pain is the most common symptom.