Euro-Chinese consensus on accessory cavitated uterine malformation*,†.

Treatment aims to alleviate pain and to restore normal anatomy. Reported ACUM management options range from medical treatment to surgery. Factors that influence decision-making include the severity of symptoms, age, and patient preferences. 25 , 33 , 34 Surgery is considered the definitive treatment for ACUM and has shown excellent results in symptom relief, pregnancy prognosis and long-term management. 10 , 22 , 23 , 24 , 25 , 28 , 34 , 35 , 36 There is no direct evidence to guide the timing of ACUM surgery or on the role of preoperative gonadotropin-releasing hormone (GnRH) agonist therapy. Surgical approaches include laparoscopy, robot-assisted laparoscopy, and laparotomy 10 , 23 , 37 and they involve the excision of the ACUM. Irrespective of the surgical approach, a systematic approach is required. Firstly, incision and circumferential enucleation of the ACUM is performed with or without preceding injection of dilute vasopressin along the uterine-ACUM interface for haemostasis. It should be noted that finding the cleavage plane can be challenging, as the typical pseudocapsule present in fibroids will not be found in ACUM. Assisted by ancillary instruments, such as a tenaculum or suction device, the procedure is completed by transecting the ACUM from its attachment and closing the uterine defect with sutures. Considering that ACUM is a benign condition, its contents are not thought to pose any threat if they leak. Thus, various techniques, such as morcellation and specimen retrieval in endo bags, have been described for removing specimens of ACUM. 31 Adhesion barrier agents can be used during surgery to prevent postoperative adhesions. 35 The boundaries of an ACUM can sometimes be imprecise and so some authors have described using intraoperative ultrasound to help with lesion localisation and excision, 31 also using intraoperative 3-dimensional ultrasonography, which not only can clearly locate the nodule but also show the thickness of the myometrium overlying the cystic cavity. 36 For older patients who do not desire future pregnancies, hysterectomy may be recommended as it offers permanent relief from dysmenorrhea. Total laparoscopic hysterectomy is a common, safe, and minimally invasive option for women with benign gynaecological conditions like ACUM. 33 Medical treatments for ACUM generally focus on pain relief and symptom management and are based on non-steroidal anti-inflammatory drugs (NSAIDs) and analgesics or on hormonal treatments [include continuous oral contraceptive pills (OCPs)], 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 the levonorgestrel-releasing intrauterine system (LNG-IUS, e.g., Mirena), and gonadotropin-releasing hormone agonists (GnRHa). 22 , 38 These therapies may temporarily reduce symptoms, allowing patients to defer or avoid surgery or to help them manage their symptoms while awaiting surgery. 44 It is unclear whether factors such as age at the start of treatment, the size of the ACUM, or other morphological characteristics influence the success of medical treatment. 31 However, if medical treatment is not effective, conservative minimally invasive surgery should be considered, always considering fertility preservation in young patients. 40 An alternative treatment is sclerotherapy with ethanol, as described by Merviel et al. 45 The procedure typically involves general anaesthesia and ultrasound guidance to insert a needle through the vaginal wall and into the ACUM. After aspirating the cyst’s contents, 96% ethanol is injected to fill the cavity for about 15 minutes, then drained. This method can offer temporary relief from symptoms but is rarely a permanent solution. Risks include leakage of the sclerosing agent into the peritoneal cavity. More recently, lauromacrogol has also been introduced as a sclerosing agent for ACUM. 46 This compound offers the dual benefits of sclerotherapy and local anaesthesia, although its long-term efficacy and safety remain under investigation. Radiofrequency ablation has also been used with similar results as ethanol sclerotherapy in terms of symptom relief. 47 , 48 • Treatment aims to restore uterine anatomy through excision of the ACUM and to alleviate symptoms. • ACUM typically requires treatment in case of severe dysmenorrhea or chronic/recurrent pelvic pain. • Surgical management, consisting of ACUM removal from the myometrium and suturing of the uterine defect, is the definitive treatment, and it has shown nearly complete remission of symptoms. Options include laparotomy, laparoscopy, and robot-assisted laparoscopy. A minimally invasive approach should be preferred when possible. • Medical management including administration of NSAIDs, OCP, LNG-IUS, and GnRH agonists. Medical management provides temporary relief but is often not a definitive solution. • Sclerotherapy is an alternative for those who wish to avoid surgery, though it may lead to recurrence. The surgical management of ACUM requires a meticulous approach to achieve complete lesion excision while preserving myometrial integrity. Optimal outcomes depend on precise surgical techniques, surgeon expertise in minimally invasive gynaecologic surgery, and selective use of intraoperative imaging guidance when necessary. • Ability to accurately estimate the penetration depth in the myometrium to remove the lesion while minimising risks. • Use of intraoperative ultrasound, including 3D ultrasonography, for precise localisation and excision of the ACUM. • Surgical skills and experience to apply proper surgical techniques including careful enucleation of the ACUM using mechanical, monopolar or bipolar energy, with various tools assisting in the dissection and suturing (especially for laparoscopy/robotics). The optimal timing for surgical intervention in ACUM remains poorly defined due to limited evidence, but clinical decisions should prioritise symptom severity, reproductive goals, and patient priorities. • There is no direct evidence to guide the timing of ACUM surgery. There is no direct evidence to guide decision making on the interval before embarking on pregnancy. • After surgery for ACUM, a recommended waiting period of 4-6 months is advised before attempting pregnancy; this allows the proper healing of the myometrium. The mode of delivery following ACUM excision lacks standardised guidelines due to insufficient outcome data, necessitating individualised decision-making based on surgical characteristics and obstetric context. Delivery planning should account for the depth of myometrial resection during ACUM excision, analogous to the FIGO classification for fibroids (e.g., FIGO type 4–5 lesions involving >50% myometrial thickness may warrant heightened surveillance for uterine rupture). • There are no data to determine the optimal mode of delivery after ACUM excision. Caesarean sections and vaginal deliveries are described in literature. In determining the mode of delivery after ACUM excision, consideration should be given to the depth of myometrial involvement/FIGO type of ACUM.

There remains a great deal that is unknown about ACUMs, which provides challenges for clinicians managing patients with this malformation. The embryological origin remains unclear, although it´s possibly related to a gubernaculum dysfunction or abnormal traction. Existing classification systems, except for Acién´s, while widely utilised, do not adequately incorporate ACUM. To diagnose an ACUM, the following criteria should be fulfilled: to be an isolated cavitated lesion located in the anterolateral myometrium, in the proximity of the round ligament, with a cavity lined by endometrial tissue and typically filled with haemorrhagic/menstrual fluid. They should be surrounded by a myometrial mantle with typical concentric orientation of the myometrial fibres, with a normal uterine cavity. Current management strategies prioritise complete surgical excision of the lesion, preferably via minimally invasive techniques, to achieve symptom resolution. There is a paucity of high-quality evidence to guide clinical decision-making regarding aspects of optimal surgical intervention and, more specifically regarding the management of future pregnancies.