Peritubal Endometriosis Discovered During Surgery for Ovarian Torsion in an Adolescent Without Dysmenorrhea: A Case Report

Endometriosis is often investigated in adolescents because of dysmenorrhea or chronic pelvic pain. We report a 15-year-old girl with previously painless menstruation who presented with abrupt severe right lower-quadrant pain and nausea. Ultrasonography suggested marked right ovarian enlargement and an 8.4-cm adnexal cyst; Doppler flow was present but showed elevated resistance. Urgent laparoscopy confirmed right ovarian torsion. The ovary was detorsed and preserved, and a cyst arising from the right fallopian tube/peritubal region was excised. Histopathology identified endometriosis with vascular congestion. Postoperative recovery was uncomplicated. A right-sided cyst was documented on subsequent imaging; later ovarian measurements decreased. This case underscores that endometriosis may be discovered during an acute adnexal emergency without preceding menstrual symptoms and that ultrasonography may not establish the precise origin of a large adnexal lesion.