Hydrosalpinx is a rare cause of abdominal pain in paediatric patients, though cases are documented in the literature. Its aetiology differs considerably from traditional hydrosalpinx due to ascending sexually transmitted infection. Hydrosalpinx can resent mimicking an acute abdomen or can be asymptomatic. Management of paediatric hydrosalpinx varies but often involves surgical removal of the affected tube. A 12-year-old girl presented with left-sided acute abdominal pain setting within 24 h. Initial ultrasound scan suggested presence of hydrosalpinx. Post-discharge follow-up appointment with a consultant paediatric gynaecologist demonstrated no symptomology, but repeated scan by another sonographer showed continued presence of possible hydrosalpinx, which had since grown. Later, MRI was performed to confirm site of the lesion. However, MRI revealed no tubal masses, suggesting spontaneously resolved hydrosalpinx. Consultant-administered ultrasound scan confirm no tubal abnormalities. Our case suggests spontaneous resolution in possible paediatric hydrosalpinx. Our recommendation is for conservative management of asymptomatic paediatric and adolescent hydrosalpinges, with emergency surgery offered if symptoms indicative of tubal or adnexal torsion.