To the Editor:
We read with great interest the case reported by Liang et al. of a uterus-like mass in a 17-year-old female – located in the left broad ligament immediately adjacent to the uterus – but “without definitive connection to the uterus.”(1) The uterus, uterine ligaments, fallopian tubes and ovaries were described as normal. The authors postulated coelomic metaplasia as the likely pathogenesis.
We suggest the theory of müllerianosis – developmentally misplaced müllerian tissue – offers a more powerful explanation for the pathogenesis for this parauterine uterus-like mass. In 2007, we defined müllerianosis by clinical-pathologic criteria as a heterotopic organoid structure of embryonic origin, a choristoma composed of müllerian rests – normal endometrium, normal endosalpingeal tissue, and normal endocervical tissue – incorporated singly or in combination within other normal organs during organogenesis. (2) Subsequently, Signorile et al. demonstrated the presence of ectopic endometrium in four human fetuses, empirical evidence supporting the theory of müllerianosis. (3)
Viewed from the perspective of pathogenesis, müllerian choristomas with three müllerian tissues can be diagnosed with confidence – and müllerian choristomas with two müllerian tissues can be diagnosed with a high degree of probability – wherever found. However, suspected müllerian choristomas with only one müllerian tissue – such as this parauterine uterus-like mass – can be diagnosed with a high degree of probability only when three criteria are met:  no evidence of pelvic endometriosis,  no direct communication with the endocervix, endometrium, or endosalpinx, and  no history of surgery on the reproductive organs. Regarding the third criterion, before this patient had surgical removal of a left mesosalpinx cyst, the parauterine uterus-like mass was present but it had been “misdiagnosed as a septate uterus.” (1)
Ronald Elmer Batt, M.D., Ph.D.
Department of Gynecology-Obstetrics
School of Medicine and Biomedical Sciences
State University of New York at Buffalo
Buffalo, New York
1. Liang Y-J, Hao Q, Wu Y-Z, Wu B. Uterus-like mass in the left broad ligament misdiagnosed as a malformation of the uterus: A case report of a rare condition and review of the literature. Fertil Steril 2010;93:1347-50.
2. Batt RE, Smith RA, Buck Louis GM, Martin DC, Chapron C, Koninckx PR, Yeh J. Müllerianosis. Histol Histopathol 2007; 22:1161-1166.
3. Signorile PG, Baldi F, Bussani R, D’Armiento M, De Falco M, Baldi A. Ectopic endometrium in human foetuses is a common event and sustains the theory of müllerianosis in the pathogenesis of endometriosis, a disease that predisposes to cancer. J Exp Clin Cancer Res 2009;28:49-53.
Published online in Fertility and Sterility doi:10.1016/j.fertnstert.2010.04.030
The authors declined to respond.