Abstract
INTRODUCTION: Ovarian pregnancy is a rare form of ectopic pregnancy, accounting for approximately 3 % of cases, with an incidence ranging from 1 in 2100 to 1 in 7000 pregnancies. Its diagnosis is challenging due to nonspecific symptoms and difficulty distinguishing it from corpus luteum cysts or tubal pregnancies. Delayed recognition can lead to life-threatening hemorrhage. PRESENTATION OF CASE: A 34-year-old gravida 3 para 3 Japanese woman presented with acute abdominal pain and hypovolemic shock 33 days after her last menstrual period. Imaging revealed a right ovarian cystic mass, intra-abdominal bleeding, and an empty uterus. Emergency laparoscopy identified a 5-mm gestational sac-like lesion on the right ovary. Laparoscopic wedge resection was performed. Pathological analysis confirmed extravillous trophoblast invasion into ovarian stromal vessels. A corpus luteum was observed at a separate location, supporting the diagnosis of secondary extrafollicular ovarian pregnancy. The patient recovered uneventfully. DISCUSSION: Ovarian pregnancies are classified as primary or secondary, and intrafollicular or extrafollicular. This case demonstrated secondary extrafollicular implantation with vascular invasion. Updated diagnostic criteria emphasize intact fallopian tubes, hemorrhagic ovarian lesions, and pregnancy tissue identification. Early detection remains difficult, particularly before 5 weeks gestation, and diagnosis often requires surgical and pathological confirmation. CONCLUSION: This case underscores the importance of early recognition and laparoscopic management of ovarian pregnancy. Pathological findings aid in understanding implantation mechanisms and differentiating from similar adnexal conditions. Minimally invasive surgery enabled successful hemostasis and fertility preservation. Improved clinical awareness is essential to reduce complications associated with this rare condition.