Cystic lesion with lipid layering in keeping with a dermoid cyst, with ultrasound and MRI correlation. Subsequent histopathology confirms a mature cystic teratoma, with features of previous rupture - this would account for the serpiginous, exophytic appearance extending from the left ovary into the pouch of Douglas.

Note aspects of the ultrasound examination that were targeted to the search for features of deep infiltrating endometriosis, based on the patient's history: evaluation of uterosacral ligaments, bladder and rectal wall.