RESUMEN
BACKGROUND: Persistent adnexal masses increase the risk of pregnancy complications including cyst rupture, ovarian torsion, and labor obstruction. Treatment options include observation, surgical excision, and early first or second trimester drainage. Our case represents the most advanced gestational age for intervention with percutaneous drainage. CASE: A 32-year old G3P1102 at 29.2 weeks gestation presented with left lower quadrant pressure, right abdominal fullness, and left uterine displacement. She had a right, simple-appearing ovarian cyst, which had increased in size from previous ultrasounds to 12.8 × 13.4 × 15.7 cm. Ultrasound-guided percutaneous drainage with pigtail catheter placement removed 1.2 L serous green fluid. Fluid culture was negative and cytology showed no evidence of malignancy. The pigtail catheter was removed at 31.2 weeks because of pain at the surgical site and significant cyst regression. The cyst resolved and she delivered via uncomplicated vaginal delivery at term. CONCLUSION: A few case reports describe first and second trimester percutaneous or transvaginal drainage of symptomatic ovarian cysts as a less invasive approach than surgical excision. However, our case suggests drainage of a simple-appearing cyst as an alternative treatment option in the third trimester when the risk of preterm labor and fetal complications with surgical intervention is at its highest.