A Progressive Huge Accessory Spleen in the Greater Omentum

Huge accessory spleen (AS) is a rare condition difficult to diagnose. We recently treated a Japanese woman with a progressive huge AS. She had a history of aortic valve replacement for aortic stenosis 1 month prior. At that time, a 4-cm AS had been detected by the preoperative computed tomography (CT). This mass was a progressive tumor which grew to 7 cm over the course of 3 months. Thus, we performed surgery with a preoperative diagnosis of huge AS by CT and positron emission tomography. A laparoscopic resection was performed considering the risk of torsion, spontaneous rupture, or hemorrhage. The final pathological diagnosis was AS. This is the first reported case in the English literature of progressive AS with no symptoms at the initial presentation that was treated with laparoscopic resection.