Endometrioma: Meaning in a Radiology Report

Endometrioma

Also written as: chocolate cyst, endometriotic cyst, ovarian endometrioma

An endometrioma is a cyst on the ovary filled with old blood, caused by endometriosis. It is often called a chocolate cyst.

Seen on: Ultrasound, MRI

How it reads in a report

A 3.8 cm unilocular left ovarian cyst with homogeneous low-level internal echoes is consistent with an endometrioma.

What it means

In endometriosis, tissue similar to the lining of the uterus grows outside it. On an ovary, this tissue can bleed a little with each cycle. Over time it forms a cyst of thick, dark old blood, hence the name chocolate cyst. On ultrasound the fluid looks evenly hazy, like frosted glass. On MRI old blood looks bright on T1 images and often darker on T2 images, a sign called shading.

When it matters

Endometriomas are benign, but unlike cycle-related cysts they usually persist. They matter because they signal endometriosis, which can cause pelvic pain, painful periods and fertility problems. Many are watched with ultrasound. Depending on symptoms, size and pregnancy plans, your doctor may suggest hormone treatment or surgery. Rarely, cancer develops in an endometrioma, so new solid parts get a closer look.

Questions to ask your doctor

Are there signs of endometriosis elsewhere in my pelvis?
Could this cyst affect my fertility or my egg reserve?
How often should it be checked, and what changes would matter?

General information, not medical advice. What a finding means for you depends on your symptoms, your history and the images themselves, so talk your results through with a doctor.