The Mayer-Rokitansky-Küster syndrome. An analysis of its morphology and embryology. Part I: Morphology.

The histological appearance of the rudimentary uterus, endometrium, uterine tube, Gartner's duct, round ligament, vagina and ovary is described in ten case of the MRK syndrome. When the layout of the pelvic contents of patients with this syndrome is compared with that of a normal embryo of 20 mm CRL (stage 20), the following conclusions may be drawn. The MRK syndrome can be regarded as resulting from the cessation of development of the Müllerian duct, which in this condition extends only as far as its attachment to the caudal mesonephric ligament, the round ligament. The adjacent structures beyond this point, which include the connecting strand and smooth muscle bundles dorsal to the bladder and vaginal rudiment, are derivatives of the Wolffian duct or Gartner's duct respectively. Our findings suggest that this syndrome is due to a deficiency of the estrogen and gestagen receptors. This deficiency may inhibit the further development of the embryonic Müllerian duct and account for the subsequent faulty differentiation of its existing elements. It is still undecided why, in cases of the MRK syndrome, development of the Müllerian duct ceases at the attachment of the caudal mesonephric ligament (later the round ligament). Further research is necessary to answer this question.