Case Report: Accessory spleen torsion with infarction mimicking a neoplasm in a 13-year-old girl

Accessory spleen torsion is a rare cause of acute abdomen that frequently mimics neoplastic processes. Herein, we report the case of a 13-year-old girl who presented with persistent upper abdominal pain lasting one day. Imaging revealed a mass in the gastro-splenic space, initially suspected to be a neoplastic lesion. A laparoscopic resection confirmed that the mass was an infarcted accessory spleen with a tortuous vascular pedicle. This case highlights that accessory spleen torsion in adolescents can present with tumor-like imaging features. Contrast-enhanced CT revealed a 4.6 cm × 4.7 cm × 4.5 cm heterogeneous enhancing mass in the gastro-splenic space, medial to the spleen. Magnetic resonance imaging (MRI) revealed a lesion in the gastro-splenic space measuring 4.4 cm × 3.6 cm × 4.2 cm, with a 2.8 cm × 1.1 cm area that was hypointense on T1-weighted imaging (T1WI), mildly hyperintense on T2-weighted imaging (T2WI), hyperintense on diffusion-weighted imaging (DWI), and mildly hypointense on the corresponding apparent diffusion coefficient (ADC) map. Despite advanced imaging findings suspicious for a tumor, torsion of an accessory spleen should be strongly considered in adolescent patients presenting with perigastric masses. Early laparoscopic surgery allows for definitive diagnosis and curative treatment, effectively preventing diagnostic delays and unnecessary extensive resections.