BackgroundHydrosalpinx and pyosalpinx are rare gynecologic problems during adolescence, especially in girls without a history of sexual activity. They are even rarer in women with Hirschsprung’s disease (HD). We herein report a case of pyosalpinx in an adolescent girl with HD treated by transvaginal ultrasound-guided drainage.Case presentationThe present patient was a 12-year-old girl (weight 83 kg; height 159 cm; body mass index 32.8 kg/m2). She had undergone five laparotomies for long-segment HD by 2 years. Her menarche had occurred at 10 years. She was admitted with lower abdominal and anal pain. Computed tomography (CT), magnetic resonance imaging (MRI), and transvaginal ultrasound showed left pyosalpinx and abdominal abscess. Surgical drainage was necessary; however, she had a history of polysurgery and was severely obese, so laparotomy was considered to carry a high risk. Transvaginal ultrasound was deemed more likely to reach the abscess safely. Therefore, she was treated with transvaginal ultrasound-guided drainage by a gynecologist skilled in the procedure. She was discharged home after 52 days. One year and nine months after discharge, there was no reformation of either the abscess or pyosalpinx.ConclusionsAdolescent girls with HD are at risk of developing hydrosalpinx. Depending on the defecation status, pyosalpinx may also develop. As a less-invasive surgical treatment, transvaginal ultrasound-guided drainage can avoid laparotomy. Collaboration with a gynecologist is essential for the diagnosis and treatment of this clinical condition. Pediatric surgeons should communicate with gynecologists for such cases beginning around puberty for continuous follow-up.