Use of intraoperative ultrasound to aid in diagnosis and management of unusual “endometrioma"

• Diagnostic Challenge: Ovarian endometriomas have a characteristic ultrasound appearance but can be mimicked by various ovarian and non-ovarian pathologies. • Intraoperative Ultrasound Findings: A new cystic lesion with a ‘ground glass’ appearance was identified intraoperatively, not seen preoperatively. • Clinical Implication: Highlights the importance of integrating ultrasound with laparoscopy to avoid misdiagnosis and unnecessary surgical intervention. • Teaching Point: Normal bowel loops can resemble endometriomas; peristaltic activity or repeat imaging can help differentiate them. Ovarian endometriomas, have a distinct sonographic appearance. However, various ovarian and non-ovarian pathologies, can mimic their appearance, leading to diagnostic challenges. A 41-year-old woman with a regular menstrual cycle presented with severe dysmenorrhea, deep dyspareunia, cyclic dyschezia, bloating, and catamenial rectal bleeding. Over time, her symptoms worsened. Transvaginal ultrasound identified adenomyosis, superficial endometriosis in the bladder peritoneum and rectouterine pouch, and a deep endometriotic nodule in the rectouterine pouch, with no bowel or ovarian involvement Laparoscopic total hysterectomy, bilateral salpingectomy, and excision of endometriosis were planned. Intraoperative ultrasound revealed a new 14 × 12 × 12 mm unilocular cystic lesion with a “ground glass” appearance near the uterus, distinct from the ovary. Laparoscopy-guided intraoperative transvaginal ultrasound was repeated. Using Reverse Trendelenburg positioning, the lesion was identified as a normal segment of the small bowel. Surgery proceeded without complications. In this case, a targeted ultrasound examination under general anesthesia revealed a cystic pelvic lesion not previously identified. Although the lesion’s “ground glass” appearance suggested an endometrioma, its separation from the ovary and absence on earlier imaging prompted a broader differential diagnosis This case exemplifies the diagnostic complexity and clinical variability of endometriosis—or when something mimics endometriosis but is not. The necessity of side-by-side use of transvaginal ultrasound and laparoscopy emphasizes the limitations of imaging modalities alone, particularly when sonographic findings are unusual, and the importance of integrating multiple diagnostic techniques, including surgery. In future instances, when an endometrioma-appearing structure does not have classic features, bowel can be considered as an alternative structure being visualized.