The management of fetal ovarian cysts

Ovarian torsion causing the loss of an ovary represents the most common complication of fetal ovarian cysts and occurs more frequently before than after birth. Thus, treatment of fetal simple ovarian cysts should be performed antenatally; however, criteria for prenatal decompression still need to be evaluated. Previous experience of the authors showed that large simple cysts have a poor outcome, whereas preliminary attempts of their "in utero" aspiration were all successful and uneventful. The authors evaluated the outcome of fetal simple ovarian cysts after prenatal aspiration and considered criteria for this procedure. The outcome of cysts showing a prenatal ultrasound pattern of torsion also was studied.

This prospective study includes 73 ovarian cysts (48 simple, 25 showing torsion) diagnosed in 72 fetuses from June 1992 to June 1999, and followed up until spontaneous resolution or surgery. Prenatal aspiration was performed in the case of simple cysts >/=5 cm in diameter. The outcome of these cysts was compared with that of similar cysts not aspirated in the authors previous study (X(2). Cysts with an US pattern of torsion persisting at birth were operated on. The outcome of simple cysts less than 5 cm and cysts with a prenatal ultrasound appearance of torsion also was evaluated.

Prenatal decompression was performed without any complications in 14 cases: 12 (86%; 95% CI: 0.68 to 1.00) regressed subsequently; 2 (14%; 95% CI: 0.00 to 0.32) showed torsion postnatally. This outcome is significantly better than that of similar cysts not aspirated in the authors' previous study(10) (P =.0002). Among the 34 simple cysts less than 5 cm, 26 (76%; 95% CI: 0.62 to 0.90) resolved spontaneously; 8 (24%; 95% CI: 0.10 to 0.38) had complications, 7 of which showing torsion (diameter at evidence of torsion, 4.4 cm [median]; range, 3.3 to 5.2 cm). Among the 34 cysts showing torsion (25 with initial US pattern of torsion + 9 subsequently complicated simple cysts), 24 (71%; 95% CI: 0.56 to 0.86) required oophorectomy; 9 (26%; 95% CI: 0.11 to 0.41) spontaneously disappeared at ultrasound, one of which required surgery for intestinal obstruction secondary to adhesion of a necrotic ovary; one patient (3%; 95% CI: 0.00 to 0.09) was lost to follow-up.

Prenatal aspiration of ovarian cysts appears effective and safe: a "cutoff" of 4 cm should be investigated. Cysts with ultrasound pattern of torsion persisting postnatally require surgery; options for their management, when sonographically disappearing and asymptomatic, need to be investigated.