OP03.03: Accessory cavitated uterine mass in a woman with infertility: crucial role of three‐dimensional ultrasound

An accessory cavitated uterine mass (ACUM) is a rare Müllerian anomaly with a non-communicating cavity containing functional endometrium found near the uterus. This often-underdiagnosed condition presents with cyclic pelvic pain and dysmenorrhea. Its association with infertility is unclear. This case highlights the association between ACUM and infertility and emphasises the role of three-dimensional (3D) ultrasound in diagnosis. A 31-year-old nulligravid woman with cyclic pelvic pain and dysmenorrhea presented with primary infertility. On previous pelvic US, MRI, and laparoscopy, a left 1.8 cm adnexal mass suspected to be a degenerating fibroid was noted. During two infertility treatment cycles, transvaginal ultrasound (TVUS) revealed a cystic adnexal mass with cycle-dependent changes in endometrial thickness and colour Doppler imaging indicating a functional endometrium. TVUS with 3D imaging showed a mass near the mid-portion of the uterus with a central hypoechoic area. The patient underwent laparoscopic excision of the mass with complete resolution of symptoms. Pathology report revealed endometrial glands and stroma with surrounding smooth muscle proliferation consistent with ACUM. The patient conceived spontaneously and had an uncomplicated pregnancy. ACUM should be considered part of the differential diagnosis for patients with dysmenorrhea and infertility when a uterine-associated mass is present. 3D TVUS can accurately diagnose ACUM leading to appropriate treatment with subsequent symptom relief and improved fertility. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.