RESUMEN
Primary or idiopathic torsion of the greater omentum, without preexistent abdominal disease, in an uncommon cause of acute abdomen. On account of its raraness and absence of specific symptomatology, the diagnosis usually is performed at laparoscopy. This condition can be mistaken for appendicitis and in women the alternative diagnosis is usually a twisted ovarian cyst. The twisted omentum may become gangrenous and give rise to peritonitis. We report a patient with an acute abdomen with HIV infection with primary torsion fo the greater omentum. This torsion with primary infarction of the greater omentum is an infrequent cause of acute abdomen as much as in immunocompetent patients the same as in HIV positives. The elective treatment is the surgical removal.