Spontaneous Rupture of Ovarian Endometrioid Carcinoma in the First Trimester: A Case Report

Abstract

Aims: Ovarian malignancy in pregnancy is rare (1:10,000–50,000), and first-trimester spontaneous rupture is exceptional. It presents a diagnostic dilemma, often mimicking common obstetric emergencies. Presentation of Case: A 32-year-old Malay primigravida at 9 weeks’ gestation presented with an acute abdomen. A previous ultrasound at 6 weeks’ gestation identified a left ovarian cyst with complex features measuring 11 × 6 cm. Diagnosis of torsion or ruptured ovarian cyst was entertained. Emergency laparotomy revealed a ruptured 10 × 8 cm left haemorrhagic ovarian cyst, with no other concerning intraoperative findings, and conservative cystectomy was performed. Histopathology confirmed endometrioid carcinoma of left ovary, stage IC2 (grade 2). The CT scan showed no distant metastases. After multidisciplinary counselling, adjuvant carboplatin chemotherapy was administered from 18 to 34 weeks’ gestation. At 34 weeks’ gestation, a caesarean section followed by definitive surgery was performed, delivering a healthy neonate. Both mother and infant recovered uneventfully. Discussion: Torsion or ectopic pregnancy are typical diagnoses of acute abdomen in pregnancy. The rare histological subtype (endometrioid) and the exceptionally early timing of rupture are making this case unique. Management required a delicate balance between oncological safety and fetal viability. The successful use of platinum-based chemotherapy in the second trimester facilitated a favourable outcome. Conclusion: Spontaneous rupture of ovarian malignancy is extremely rare; however, it should be considered a differential diagnosis for acute abdomen in pregnancy. Timely multidisciplinary management can optimise outcomes for both mother and neonate.