To introduced the diagnosis and treatment of an oversized accessory spleen case. It suggested that clinician should be alert to the existence of giant accessory spleen, and reduced misdiagnosis and mistreatment. During operation, must keep in mind to the diversity of blood supply of accessory spleen and less bleeding.

In this retrospective study, a patient suffering a left upper abdominal mass was performed by laparoscopic surgery, and the diagnosis and treatment were recorded with preoperative imaging data and pathological results after operation.

Laparoscopic splenectomy was performed.The supplied vessels of the oversized accessory spleen were ligated properly and prevented other adverse effects. Postoperative pathology confirmed accessory spleen combined with hemorrhage and infarction.Patient discharged uneventfully 3 days later.

This oversized accessory spleen case was rare. And the patient had the indication of splenectomy. The treatment by minimally invasive approach was feasible and safe.