Complex Müllerian malformation: report of a case with a hypoplastic non-cavitated uterus and two rudimentary horns

Various classifications have been used for congenital anomalies of the Müllerian system. We report a case of a previously unknown anomaly of the uterus, and propose its possible embryological causes. The patient presented with primary amenorrhoea and infertility, and during laparoscopy three distinct uterine horns were observed. The tubes were connected to the two most lateral horns, each juxtaposed to a normal ovary. The middle horn had a seemingly normal attachment to the right uterosacral ligament, whereas its attachment to the left uterosacral ligament appeared attenuated and less normal. Furthermore, the right horn was immediately attached to the middle horn, whereas the left horn was, like its ipsilateral uterosacral ligament, attached to the middle horn by a more attenuated, stretched fibrous bridge. Only the middle horn, with its uterosacral ligaments, had an attached, although obstructed, cervix. Ultrasonographic examination revealed no endometrium echogeneity in any of these uterine bulbs. No etiologic factors were noted in the patient's history; her mother denied known ingestion of estrogens or other drugs while carrying her daughter. The pathogenesis of this anomaly cannot be clearly defined, but may involve sequential embryological errors of duplication of the Müllerian tracts, failure of fusion of each set of the Müllerian tracts with expected failed canalization of each tract and, finally, agenesis of the medial horn of the left duplicated tracts.