A rare case of the new entity of müllerian anomalies mimicking the noncommunicating rudimentary cavity with hemi-uterus: accessory cavitated uterine mass

Accessory cavitated uterine mass is a very rare case of mullerian anomalies and should be categorized in a different class.
A rare case of the new entity of müllerian anomalies mimicking the noncommunicating rudimentary cavity with hemi-uterus: accessory cavitated uterine mass


Vehbi Yavuz Tokgoz, M.D., Ahmet Basar Tekin, M.D.



To demonstrate the laparoscopic excision of an accessory cavitated uterine mass (ACUM) and show that atypical anomalies can lead to the misdiagnosis of a noncommunicating rudimentary horn.


Description and step-by-step demonstration of the surgical procedure using a video recording (Canadian Task Force Classification 3).


University hospital.


A 17-year-old virgin girl with chronic pelvic pain and severe progressive dysmenorrhea despite using nonsteroidal anti-inflammatory drugs and oral contraceptives since her menarche. We could not perform transvaginal examination and ultrasonography because of the virginity of the girl. Transabdominal ultrasound revealed a 24 × 24-mm heterogeneous cystic mass on the left adnexal region suggesting a noncommunicating functional rudimentary horn. This mass was within the left lateral uterine myometrial wall, and otherwise, the uterus and endometrial cavity seemed normal on ultrasonographic examination. Magnetic resonance imaging showed a cavitated nodule of 25 mm with hemorrhagic components inside the mass on the left side of the uterus and the normal endometrial cavity with a normal size uterus. After detailed evaluation and counseling, a decision was taken to perform laparoscopy.


Laparoscopic resection of the ACUM.

Main Outcome Measure(s)

On laparoscopic exploration, we first observed a globular enlargement on the left wall of the uterus under the round ligament. Both the ovaries and the uterus were normal, and there were two normally developed fallopian tubes with no abnormality communicating with the normal uterus. The mass had irregular muscle fibers and ambiguous limits for detaching from the normal myometrial tissue. Afterward, the mass was resected completely without entering the endometrial cavity. It was thought that these irregular borders may be a factor of confusion as a degenerated myoma on the diagnosis. The blunt and sharp dissection methods were used bidirectionally, and finally, the lesion was enucleated. The mass was incised, and chocolate-like brownish fluid spilled out from the cavity of the mass. The endometrium-like epithelium and surrounding muscular layer were seen on the mass. The myometrial defect was approximated and closed with a polyglactin absorbable suture. Histopathological examination revealed the endometrial lining cavitated mass surrounded by myometrium, and thus, it was consistent with the diagnosis of ACUM.


The postoperative period of the patient was uneventful. She was discharged without any complaint. Her severe pelvic pain and symptoms of dysmenorrhea were resolved 1 month after the surgery. We did not prescribe any medication for menstrual suppression and pain management before or after surgery. During the follow-up period, she had a regular menstrual cycle and no pelvic pain and dysmenorrhea for 2 years.


Accessory cavitated uterine mass is a new entity having a normal endometrial cavity and is different from other müllerian duct anomalies. Severe dysmenorrhea and chronic pelvic pain are early-onset, and they are persistent despite using medications, but suspecting this problem is the main determinant for confirming the diagnosis. The final diagnosis of ACUM can be made after resecting the mass and confirming with histopathological examination. Accessory cavitated uterine mass may be confused with a similar lesion of juvenile cystic adenomyosis (JCA). They present very similar clinical and pathological findings, but JCA is a rare form of focal adenomyosis that contains cystic contents inside the lesion, and it has more intense adenomyosis surrounding the endometrial lining of a cavitated mass. In our case, histopathological examination revealed muscle fibers around the endometrial epithelium, with no adenomyotic foci. It was so difficult to distinguish these two similar lesions during the surgery. Thus, we could distinguish ACUM from JCA with this pathological confirmation. Accessory cavitated uterine mass may also be misdiagnosed as U4a of ESHRE/ESGE classification and 2b of ASRM classification, but it should be distinguished from these anomalies. Moreover, it is important to define ACUM clearly in the U4 or U6 class of the ESHRE/ESGE and 2b of ASRM classification systems.