Objective: To present clinical cases of women who had an accessory and cavitated noncommunicating uterine mass with functioning endometrium associated with a normal uterus, suggestive of a new type of Müllerian anomaly.
Methods: We report on five institutional cases: four cases of cavitated accessory uterine mass and a case of true adenomyoma. A review of the literature was performed by looking for these terms and others related in MEDLINE.
Results: Including ours, there are 18 cases in the literature showing an accessory cystic cavity lined by endometrioid epithelium with an otherwise normal uterus. Another 11 cases only partially fulfilled the inclusion criteria. All of the first cases were in young women presenting with severe dysmenorrhea (n=4). Generally, the tumor was located in the anterior wall of the uterus at the level of insertion of the round ligament. It presents a certain similarity with the cavitated true adenomyomas observed in older women in whom the endometrial lining of the cystic cavity is generally absent. For differential diagnosis with cavitated noncommunicating rudimentary uterine horns, hysterosalpingography showing a normal eutopic uterine cavity is decisive.
Conclusion: Noncommunicating accessory uterine cavities and isolated cystic adenomyomas correspond to the same pathology: cavitated accessory uterine mass associated with an otherwise normal uterus. They present problems of differential diagnosis with true cavitated adenomyomas and cavitated rudimentary uterine horns. Accessory uterine mass could be caused by duplication and persistence of ductal Müllerian tissue in a critical area at the attachment level of the round ligament, possibly related to a gubernaculum dysfunction.
Level of evidence: III.