What does endometriosis show on a pathology report?

On a pathology report, endometriosis is typically described as endometrial-type glands and stroma found outside the uterus. Pathologists may also note supportive findings such as old or recent bleeding and iron-laden (hemosiderin) macrophages, which are signs the tissue has been hormonally active and bleeding over time. The report often lists the site the tissue came from (for example, pelvic peritoneum, ovary, bowel surface, bladder peritoneum) and may comment on the pattern, such as superficial implants, deeper fibrotic/nodular disease, or an ovarian endometrioma.

It’s also common for pathology to come back as “no endometriosis identified” even when symptoms are very real—or even when lesions looked suspicious in surgery—because confirmation depends on getting the right tissue from the right spot. Endometriosis can be subtle, patchy, or sit beneath a normal-looking surface, so sampling technique and lesion location matter. If you have a report you’re trying to decode, our team can help you understand what the wording means in the context of what was seen during surgery and what it suggests about next steps.