Acute abdomen: Unusual presentation of Herlyn-Werner Wunderlich syndrome

The presentation of an acute abdomen has a wide range of differentials. Developmental anomalies are rarely considered as part of the clinical reasoning process due to it being a mimicker of other commoner diseases. The importance of considering such anomalies and recognizing them early is essential in order to prevent complications, such as infertility. Our case report presents an approach to a female of pediatric age complaining of right lower abdominal pain mimicking appendicitis. The physical examination and clinical findings were also in line with appendicitis. Thus, the initial work-up focused on that as the top differential. Due to the patient being female, other work-ups were conducted in order to rule out gynecological conditions such as a pelvic ultrasound. The ultrasound findings changed the approach, warranting a CT and MRI. The subsequent diagnosis was Herlyn-Werner-Wunderlich Syndrome. Intervention involved incision and dilation of the vaginal septum as it is the most effective and least traumatic method. On follow-up, the patient's symptoms resolved. Rare diseases can mimic common diseases. Clinically, findings of other work-ups indicated a completely different diagnosis than originally suspected. Clinical reasoning thus shifted the focus to another approach and intervention. Clinical features of appendicitis, a clinical diagnosis, were most evident. An inappropriate management may have ensued if investigations were not conducted. Ultimately, the case report illustrated the importance of radiological investigations in an acute abdomen. •An unnecessary appendectomy was avoided by considering acute abdomen mimickers.•The usual ‘acute abdomen’ should include unusual developmental anomalies.•Early recognition of rare syndromes, such as HWW syndrome, prevents complications.•Preserving fertility in HWW syndrome is key and is preventable if detected early.