The authors report a case of benign non secretory islet cell tumour. Ten other cases of this type were found in the literature. These non-functional tumours évolve without symptoms and are rarely diagnosed in the presence of an abdominal mass. They are usually discovered at autopsy. Clinical examination and further investigation do not always demonstrate the pancreatic origin of the tumour observed. Treatment is surgical consisting of removal of the tumour. Pathological examination leads to the diagnosis of non-secretory islet cell tumour which is usually benign; only the course can confirm this.