Primary Abdominal Ectopic Pregnancy Involving the Spleen: A Case Study.

Introduction: Ectopic pregnancy, affecting 1%-2% of pregnancies, is a major cause of first-trimester maternal morbidity and mortality, most commonly occurring in the fallopian tubes. Abdominal ectopic pregnancy is rare (< 1%) but highly dangerous, with risk of hemorrhage, infection, and misdiagnosis. Splenic implantation is exceptionally rare. Diagnosis relies on ultrasound, MRI, and beta-hCG levels, though symptoms are often nonspecific. Risk factors include tubal disease, infections, prior surgery, and assisted reproduction. Early diagnosis is critical, as maternal and perinatal mortality are high. Management is usually surgical, with laparoscopy preferred in stable early cases and laparotomy in more advanced or complicated presentations. Case Presentation: A 29-year-old gravida 2 para 1 at 5 + 4 weeks presented with mild vaginal bleeding and stable vital signs. Serum beta-hCG levels showed an abnormal rise followed by a plateau. Transvaginal ultrasound revealed no intrauterine pregnancy, suggesting a pregnancy of unknown location, with a suspicious right-sided adnexal finding. A second-level ultrasound identified a vascularized multilocular mass near the anterior uterine recess, raising concern for ectopic or abdominal pregnancy. Due to diagnostic uncertainty and plateauing beta-hCG, exploratory laparoscopy was performed. The pelvis appeared normal, but two vascularized formations were found on the prevesical peritoneum and excised. Postoperatively, beta-hCG levels declined significantly. Histological analysis confirmed first-trimester chorionic villi and trophoblast cells within splenic tissue, consistent with ectopic pregnancy implanted in splenosis. The patient recovered well and was discharged in stable condition with near-complete resolution of beta-hCG levels on follow-up. Discussion: Abdominal pregnancy is a rare, life-threatening ectopic pregnancy with a challenging diagnosis. In this case, inconclusive imaging and plateauing beta-hCG prompted laparoscopy, confirming prevesical implantation. Prior splenectomy may have contributed. Surgical removal led to resolution, highlighting the importance of systematic evaluation, clinical suspicion, and timely intervention in atypical ectopic pregnancies.