Rectosigmoid endometriosis - mushroom cap sign

Case contributed by Gustavo Aguiar
Diagnosis almost certain


Pelvic pain.

Patient Data

Age: 35 years
Gender: Female

MRI shows an endometriotic lesion in the rectosigmoid junction that shows a "mushroom cap" sign. There is another endometriotic lesion in the posterior uterine serosa extending to anterior rectal wall.

Mild thickening of the junctional zone of the uterus and small areas of cystic change consistent with adenomyosis, and right ovarian endometrioma are also noted

Annotated image

The low-signal-intensity base of the mushroom is the endometric lesion (asterisk), whereas the high-signal-intensity cap represents the mucosa and submucosa (arrows), which are displaced into the bowel lumen.

Case Discussion

The MR imaging features of solid rectosigmoid endometriosis include a “mushroom cap” sign, which is considered a specific finding of solid invasive endometriosis of the rectosigmoid colon on T2-weighted MR images

How to use cases

You can use Radiopaedia cases in a variety of ways to help you learn and teach.

Creating your own cases is easy.

Updating… Please wait.

 Unable to process the form. Check for errors and try again.

 Thank you for updating your details.