INTRODUCTION: Interstitial pregnancy, a rare form of ectopic pregnancy, occurs when implantation happens in the uterine wall's intramural tubal segment. Though uncommon, it carries high risks like hemorrhagic rupture, necessitating early diagnosis and prompt management. CASE PRESENTATION: A 33-year-old primigravida patient with no medical or surgical history and no particular risk factors presented with acute abdominal pain and minimal metrorrhagia. Physical examination revealed minimal uterine bleeding and slight pain on uterine mobilization. Ultrasound showed an enlarged uterus with a visible cavity and the presence of a right lateral uterine mass in favor an interstitial pregnancy. Laparotomy, which confirmed the diagnosis was done with a salpingectomy and cornuotomie. DISCUSSION: Interstitial pregnancy is a rare and potentially life-threatening form of ectopic pregnancy, constituting only 2.4 % of cases. It differs anatomically from other types like angular or cornual pregnancies and poses a high risk of uterine rupture and severe hemorrhage due to delayed diagnosis. While β-hCG kinetics may offer clues, diagnosis primarily relies on transvaginal ultrasound, with MRI or 3D ultrasound as supplementary tools in complex cases. Treatment can be medical or surgical with laparoscopy preferred when available. Obstetric outcomes are generally favorable, with some cases supporting elective cesarean delivery as a precaution. CONCLUSION: Early diagnosis is crucial to prevent the potentially life-threatening progression of interstitial pregnancy
therefore, this condition should be considered in women who present with abdominal pain and/or vaginal bleeding during the first trimester.