We report a case of a spleen infarction caused by the vascular pedicle torsion. A 25 year-old-man, heterozygous for HbS, presented with severe abdominal pain especially in the left upper quadrant in front and in the back, fever other symptoms related to acute abdomen. First we excluded most common disease (occlusive one and hematologic one) through conform investigation, then we suspected a spleen problem. So we did further investigation with ultrasonography which showed splenomegaly and the spleen looked twisted with its hilum in contact with previous abdominal wall, moreover (here were are as of decreased signal intensity characteristic of splenic infarction under the capsule and some blood in the Douglas pouch. The patient underwent splenectomy urgently. During the intervention we saw a splenomegaly like the ultrasonography showed, moreover there were a long twisted vascular pedicle and many areas of infarctions, some of which had ruptured causing emoperitoneum. The surgical intervention was successful and the clinical spectrum was solved. The splenic infarction might be clinically silent or to represent a surgical emergency. In front a case of acute abdomen, after exclusion of most common etiology, we underline the importance to suspect a spleen suffering, especially vascular one, when (here was no history of trauma. Considering this fact, a simple not invasive examination like ultrasonography is able to confirm this kind of hypothesis and to give soon information to make the surgical choose.