Natural Progression of Possible In-utero Ovarian Torsion

Abstract

<h3>Background</h3> Fetal intra abdominal cystic masses can be detected by routine antenatal ultrasound. The differential diagnosis most commonly includes masses related to the genitourinary (kidney or ovary) or gastrointestinal tract. The most common types of ovarian cysts are follicular and theca-lutein cysts, and the risk of malignancy in this age group is extremely unlikely. Complications of a fetal uyarian cyst include torsion, hemorrhagc, intestinal obstruction, and birth dystocia. <h3>Case</h3> A 25 year-old gravida-4 para-3 with an uncomplicated prenatal course presented for an ultrasound at 32.9 weeks gestation due to fundal height greater than dates and a previous child with congenital anomalies. The survey was normal except for a 4.0cm × 2.8cm × 3.8cm cystic structure in the left fetal pelvis, separate from the bladder and kidney, thought to be consistent with an ovarian cyst. A healthy female (10 pounds 12 ounces) was delivered vaginally at term. The ovarian cyst was asymptomatic, as the baby had normal feeding and growth. At 4 months of age, an ultrasound showed a 1.8cm × 2.9cm hypoechoic lesion with internal echoes in the left upper quadrant, consistent with an ovarian cystic lesion that may have torsed or bled; the left ovary was not visualized in the pelvis, and the right ovary appeared normal. At 5 months a repeat ultrasound showed a homogenous hypoechoic mass of similar dimensions with internal echogenicity in the right lower quadrant, thought to be consistent with a mobile ovarian cyst. At 6 months, the left ovary measured 1cm × 2cm × 1.9cm and contained multiple punctate internal calcifications, with a more dense calcification medial to the left ovary; these findings were consistent with a history of prenatal ovarian torsion, although the scan was unable to exclude the possibility of a teratoma. A scan at 8 months demonstrated an ovoid mass of mixed echogenicity measuring 3.2cm × 2.1cm × 3.2cm in the left lower quadrant: the hyperechoic portion seen previously was still prominent and demonstrated posterior shadowing. The most likely possibility to explain these findings was once again thought to be a history of <i>in-utero</i> ovarian torsion. Abdominal x-ray films obtained at that time showed no pelvic calcifications. At 1 year of age, the mass was unchanged in size, with note made of a calcification along the anterior surface. An 18 month scan showed that the calcified left ovarian lesion, presumably representing an old torsion of the ovary, was unchanged. At 2 years of age, the panially calcified left ovary was seen with what appeared to be normal ovarian tissue. measuring 2.7cm × 1.1cm × 2.1cm. Venous now was obtained in the normal-appearing tissue. This finding was thought to be more suggestive of an ovarian dermoid rather than torsion. Repeat abdominal x-ray films were obtained, and again did not demonstrate pelvic calcifications. At 3 years of age, a normal left ovary, measuring 1.5cm × 1.1cm was noted to be adjacent to a stable linear calcification in the left adnexa. measuring 1.7cm. The most recent scan, obtained at 3 years and 4 months of age, showed a calcified left ovary measuring 1.5cm × 1.6cm × 1.6cm. The calcification appeared to be surrounded by normal ovarian tissue, without change from previous ultrasounds. and thought to most likely represent possible <i>in-utero</i> ovarian torsion. <h3>Conclusions</h3> A fetal ovarian cyst complicated by possible <i>in-lItero</i> torsion does not require intervention if it is asymptomatic and not increasing in size. As the cyst is asymptomatic and the risk of malignancy is extremely small, intervention is not necessary.