Herlyn-werner-wunderlich syndrome: MRI findings, radiological guide (two cases and literature review), and differential diagnosis

two cases of HWW syndrome in adolescents and a differential diagnosis for one case of a different MDA, and the impact of magnetic resonance (MR) imaging technology to achieve the correct diagnosis.MR imaging is a very suitable diagnostic tool in order to perform the correct diagnosis of HWW syndrome.The association of renal agenesis with ipsilateral blind hemivagina and didelphys uterus is reported as Herlyn-Werner-Wunderlich (HWW) syndrome; this triad was initially disclosed in an English report published in 2006 [1].The incidence of didelphys uterus, related to HWW, is approximately 1/2,000 to 1/28,000, and it is accompanied by unilateral renal agenesis in 43% of cases. The incidence of unilateral renal agenesis is 1/1,100, and 25-50% of affected women exhibits associated genital abnormalities [2].HWW syndrome represents a type of Müllerian duct anomalies (MDA) associated with mesonephric duct anomalies. MDA are congenital entities resulting from non-development (agenesia or hypoplasia), defective vertical or lateral fusion, or resorption failure of the Müllerian (paramesonephric) ducts [3].MDA are estimated to have an overall prevalence of 2% to 3% among all women, with an incidence of 1/200-600 among fertile women. Hypoplasia, as well as agenesis of the uterus and proximal vagina, accounts for 5%-10% of Müllerian duct anomalies, whereas didelphys uterus accounts for approximately 11% of Müllerian duct anomalies. Renal tract anomalies are associated with MDA in as many as 30% of cases [4].A complete or partial vaginal septum is present in 75% of women with didelphys uterus [5].The exact cause, pathogenesis and embryologic origin of HWW syndrome are unclear and remain a subject of discussion [6].HWW syndrome is usually discovered at puberty with non-specific symptoms, like increasing pelvic pain, dysmenorrhea and palpable mass due to the associated haematocolpos or hematometra, which result from retained, longstanding menstrual flow in the obstrucucted vagina.It r