A rare case of accessory spleen torsion in a child diagnosed by ultrasound (US) and contrast-enhanced ultrasound (CEUS)

Introduction: Accessory spleen, also known as supernumerary spleen or splenunculum, is a congenital anomaly of the spleen due to a fusion defect during the embryogenesis. Usually it is detected casually during an ultrasound (US) examination of the abdomen and it is asymptomatic.

Case report: RESULTS: We present a case of a 12 years old male patient, with 2-days history of left abdominal pain, without fever, gastrointestinal or genitourinary symptoms. The day before our observation, the patient had gone to another hospital, from where he had been discharged with medical analgesic therapy, without any benefit. Blood tests were normal, the Ultrasound abdominal examination showed normal aspect of abdominal organs, but the presence in the left side of a small round parenchymal structure surrounded by hyperechogenic mesenteric fat. We interpreted this image as an accessory spleen, complicated by torsion. As the torsion of accessory spleen is a quite rare occurrence, we carried out a contrast enhanced ultrasound (CEUS) to get more information. CEUS showed the absence of enhancement of the nodular formation, suggestive for a complete lack of vascularization; the spleen was normally enhanced. While the management in case of accessory spleen torsion is non-operative, in this case the patient underwent surgical exploration, due to the persistence of abdominal pain despite the medical therapy, with clinical signs of peritoneal reaction, mimicking an acute abdomen. Surgery confirmed the diagnosis of accessory spleen torsion.

Discussion and conclusions: In conclusion, US is the first diagnostic tool in pediatric abdominal pain and allows to direct the diagnosis; the use of CEUS helps to clarify the US reports, without leaving doubts about the parenchymal vascularization of the abdominal organ involved.