FETAL OVARIAN-CYST DECOMPRESSION TO PREVENT TORSION

Background/Purpose: Neonates who have ovarian torsion caused by an ova rian cyst often lose their ovary because the torsion and infarction oc curred antenatally. Because ultrasound scan has been so effective in d iagnosing ovarian cysts in utero, we have a better understanding of th eir natural history and can select appropriate cases for cyst decompre ssion in utero to prevent torsion. The authors reviewed experience wit h seven fetuses who had fetal ovarian cyst. Methods: During a 26-month period, seven patients were referred for the evaluation of fetal ovar ian cyst. The mean gestational age at presentation was 31.9 +/- 3.6 we eks (+/-SD; range, 27 to 37 weeks). There was no history of maternal r isk factors such as diabetes mellitus or fetal risk factors such as hy perthyroidism or placentomegally. All seven cases involved isolated un ilateral cysts without associated anomalies or chromosomal abnormaliti es. Mean initial cyst diameter was 3.4 +/- 1.7 cm (+/-SD; range, 1 to 6.1). Indications used for ovarian cyst decompression included anechoi c cysts with a diameter greater than or equal to 4 cm, a cyst ''wander ing'' about the abdomen on serial sonograms, or demonstrating rapid en largement (>1 cm/wk). Results: All but one cyst progressed in size dur ing observation, One fetal ovarian cyst (diameter, 2 cm) subsequently regressed spontaneously and another (diameter, 2.1 cm) stabilized duri ng prenatal ultrasound surveillance. One ''cyst'' observed with a diam eter of 3.5 cm proved to be a persistent cloaca. Four fetal ovarian cy sts met criteria for decompression. Because of fetal position, decompr ession could not be performed in one. One cyst (seen before defining c riteria for decompression) with a diameter of 5 cm was observed only a nd underwent torsion, Two cysts (diameters, 6.1 cm and 4 cm) were deco mpressed in utero under local anesthesia with ultrasound guidance, of 95 mL and 35 mL, respectively, High cyst fluid progesterone (12,041 an d 1,990 ng/dL, respectively) and testosterone (1,298 and 2,900 ng/dL, respectively) confirmed the etiology of the cyst as ovarian. Neither c yst recurred, and postnatal ultrasound scan confirmed resolution. Ther e was no maternal or fetal morbidity or mortality and only the patient observed before development of criteria for decompression lost her ov ary because of torsion. Conclusions: Fetal ovarian cysts tend to prese nt as isolated unilateral lesions in normal fetuses in the third trime ster. Spontaneous regression of fetal ovarian cysts may occur, Fetal o varian cyst decompression, in select cases, may preserve ovaries at ri sk for torsion. Copyright (C) 1997 by W.B. Saunders Company.