Rare Causes of Abdominal Mass in Infants: Hydrocolposis and Hydronephrosis Due to Imperforate Hymen

The epidemiology of pediatric abdominal masses varies according to age.Although malignant masses are more common in older children, benign masses are more common during the neonatal period and infancy.Here, we present a case of a baby with hidrocolpos and hydronephrosis due to imperforated hymen (IH).A 6-week-old female infant presented with abdominal distension after 2 weeks.The patient was admitted to our clinic after an abdominal mass was detected on ultrasonography (USG) performed at another center.Physical examination revealed abdominal distention and dullness on percussion, suggesting the presence of fluid or a mass, and a firm, non-palpable abdomen on palpation.A mass was visible on the direct abdominal X-ray.Subsequent USG performed at our hospital revealed a 10-cm cystic mass extending to the right upper quadrant of the abdomen, accompanied by hydronephrosis.Pediatric surgery was requested from the patient.IH was detected in the infant.Abdominal computed tomography revealed vaginal atresia.The patient was surgically treated with hymenotomy and pus drainage.The appearance of the mass improved on direct abdominal X-ray taken after the surgery.In conclusion, IH is a rare disease that is often missed in diagnosis.Therefore, clinicians should adopt a multisystemic approach that emphasizes the importance of thorough physical examination, including a complete genital examination.