Abstract Objective Herlyn-Werner-Wunderlich (HWW) Syndrome, also known as Obstructed Hemivagina and Ipsilateral Renal Anomaly (OHVIRA) syndrome, is a very rare congenital urogenital tract anomaly. The incidence of the syndrome is less than 1/1,000,000 females. OHVIRA syndrome radiologically presents as the Wunderlich triad: uterus didelphys, obstructed hemivagina and ipsilateral renal agenesis. Clinical presentation is progressive dysmenorrhea beginning with the menarche. If unilateral renal agenesis is diagnosed in a female newborn, gynecological exams should be performed to exclude corresponding genital anomalies. We present here a case of OHVIRA syndrome mimicking acute appendicitis. Methods A 12-year-old recently menarched female presented to our emergency department with lower abdominal pain and nausea without vomiting. The pain started two days earlier and it was the first such episode. The abdomen was tender in the right lower quadrant with no alarming signs. WBC count and CRP were normal. Abdominal ultrasound suggested acute appendicitis (without clear visualization of the appendix) and also revealed left renal agenesis. Performed abdominal MRI confirmed renal agenesis and uterine malformation with 2 uterine bodies, 2 cervical uteri and a closed hemi-vagina with hematocolpos. Results With the diagnosis of the rare OHVIRA syndrome and the visualization of a healthy appendix the cause of the pain was identified. The patient was hospitalized for one night to control pain and a treatment with oral contraception was introduced to suppress the hormonal cycle. Since pain was not well controlled the patient returned to the emergency department two days later. Indication for surgical treatment was made and the blood filled hemivagina incised, drained and marsupialised. Oral contraception (Dienogest) was prescribed. Further gynecological follow-up and corrective surgery are planned. Conclusion OHVIRA syndrome is very rare and may mislead physicians presuming other pathologies such as acute appendicitis. In young women presenting with abdominal pain, OHVIRA should be taken into account. Ultrasound and MRI are the imagery of choice, especially in fertile young women. Rapid and complete diagnosis is necessary to treat correctly and prevent complications. Moreover, detected genitourinary malformations should always lead to further investigations of concomitants pathologies.