Heterotopic pregnancy represents an unusual affection characterized by the coexistence of both intra and extra-uterine pregnancy in the same patient. We report a case study occurred in a 32 years old woman and revealed by a clinical table of abdominal mass syndrome. She was requested an ultrasound that allowed the diagnosis of a delayed abdominal pregnancy, but did not show the intra-uterine gestation. Therefore, a left annexectomy was carried out and led to a spontaneous abortion. The particularities of diagnosis, the etiopathogeny and treatment principles are discussed based on literature review.