INTRODUCTION: Etiologies for dysmenorrhea, pelvic pain, and/or abnormal uterine bleeding include endometriosis, polycystic ovarian syndrome (PCOS), endocrinological pathologies, and/or structural uterine anomalies. A rare culprit of these symptoms is an accessory cavitated uterine malformation (ACUM). An ACUM is a cavitated lesion surrounded by a myometrial mantle that is continuous with the anterolateral aspect of the uterine wall, inferior to the insertion of the round ligament and the interstitial portion of the fallopian tube (1). The true incidence of ACUM is unknown, and its pathogenesis remains unclear; however, current theories suggest a congenital defect in müllerian development (2). OBJECTIVE: We review the case of a patient who underwent evaluation with various forms of management before the ultimate identification and surgical management of ACUM. METHODS: RESULTS: A nulliparous 24-year-old with Hashimoto’s thyroiditis and a history of dysmenorrhea and irregular menses initiated her care with a primary care physician. The patient was initiated on oral contraceptive pills (OCPs), and the initial pelvic ultrasound (US) showed an anteverted uterus, a mildly complex left 3.5-cm ovarian cyst, and a 1.4-cm predominantly hyperechoic structure adjacent to the right ovary with no internal vascularity. The patient was then referred to an obstetrician/gynecologist (OB/GYN) and received care from several physicians and non-physician providers over several months. The patient was trialed on NSAIDs, combined oral contraceptive pills (COCPs), progestin pills, and the vaginal contraceptive ring. The patient also met criteria for PCOS during the workup. A subsequent pelvic MRI showed a 1.8-cm anterior uterine body subserosal fibroid with multiple bilateral ovarian follicles. Due to concerns for endometriosis, the patient was increased to 10 mg of norethindrone acetate for menstrual suppression and underwent a diagnostic laparoscopy, para-tubal cystectomy, and peritoneal biopsy with intraoperative findings suggestive of superficial endometriosis and a possible fibrotic endometriosis lesion on the right cornua. Postoperatively, the patient’s symptoms improved with norethindrone acetate and a strict no-gluten, no-dairy diet. The patient then developed prolonged breakthrough bleeding, and a repeat pelvic US showed a 1.7-cm hypoechoic lesion in the right adnexa inseparable from the adjacent fundal region of the uterus, concerning for an endometrioma versus subserosal myoma. The patient then underwent a robotic-assisted laparoscopic excision of endometriosis, excision of right ACUM, chromotubation, bilateral ureterolysis, and levonorgestrel intrauterine device insertion under the care of a gynecologic surgeon. Intraoperative findings showed a right ACUM distal to the right round ligament, bilateral patent fallopian tubes, and superficial endometriosis of the pelvic peritoneum. Postoperatively, the patient reported complete resolution of pain. CONCLUSIONS: This case illustrates a rare etiology for pelvic pain that can be surgically cured. It highlights the challenges of accurate diagnosis, which can impair the early resolution of symptoms, such as undergoing evaluations with multiple providers. Though the imaging in retrospect clearly showed an ACUM, the differential diagnosis for both the radiologists and several OB/GYNs omitted ACUM, given its rarity. This case highlights the need for increased awareness about ACUM and its associated symptoms.Figure 1Figure 2
Rossow et al. (Fri,) studied this question.