Case presentation
We present a term baby girl born to a 35-year old Caucasian woman in her first pregnancy with an uneventful medical history. Informed consent was obtained prior to publication.
Dating (12 weeks of gestation) and anomaly (20 weeks of gestation) scans were reported as normal. A growth scan was requested at 35 weeks 6 days of gestation due to a low maternal BMI of 17.84 kg/m2. Normal fetal movements were reported and there were no maternal concerns at the time of this scan.
The growth scan revealed that although the umbilical artery Doppler was normal, the estimated fetal weight was below the fifth centile. The liquor volume was adequate with a maximum pool depth of 7 cm and satisfactory fetal movements were seen. A well-rounded mass containing low level echoes was identified in the fetal pelvis superior and posterior to the urinary bladder. The fetal urinary bladder, kidneys and the stomach were demonstrated and appeared normal. No obvious mass pressure effect was seen in the fetal abdomen.
As per hospital protocol, the woman was referred to the Fetal Medicine Department for a further scan which identified a 3.5 x 3.7 x 8 cm solid mass in the abdomen behind the bladder and in the midline, most likely representing an enlarged uterus in this female fetus. The external genitalia, renal tract and bladder appeared normal. The scan confirmed that the fetus was small for gestational age. No other structural abnormalities were seen within limits of late gestational age and a probable diagnosis of a fetal hematometrocolpos was made (Figure 1A).
The woman was counselled about the findings, and a plan was made for baby to have a postnatal abdominal ultrasound scan to confirm the diagnosis and to be transferred to the surgical centre at the [blinded] Hospital for intervention. Since these findings are usually not associated with underlying chromosomal or genetic problems, amniocentesis was not offered. Increased surveillance was arranged because of the growth restriction with serial growth scans.
The baby was born in good condition vaginally by forceps assisted delivery following induction of labor at 39 weeks of gestation with a birth weight of 2625 grams. On physical examination, a protruding vaginal mass was noted, with no signs of ulceration or infection. Both femoral pulses were felt with difficulty, but there was good distal perfusion to both legs. The rest of the physical examination was unremarkable. Baby was passing urine and opening her bowels normally. Her renal function parameters were normal.
An ultrasound of the baby’s abdomen and pelvis was performed on the day of birth confirming a thin walled cystic structure filling the pelvis and extending up to the umbilicus and bilaterally into both adnexae (Figure 1B). The structure measured 7.3 x 3.1 x 6 cm and contained echogenic fluid. There was no internal vascularity demonstrated. At the superior border of the structure, a lobulated, more solid looking focus measuring 16 x 8 x 13 mm with elements of shadowing was described, suggested to be possible calcification, also with no internal vascularity. It was not possible to identify a vagina. The liver, spleen and kidneys had normal appearances and there was no hydronephrosis. The urinary bladder was virtually empty and only seen low in the pelvis and anterior to the cystic mass. The femoral vessels were patent. Overall, appearances were suggestive of a hematometrocolpos with a possible small clot at the fundal aspect.
The baby was transferred to the [blinded] Hospital and had surgery under general anesthesia on the third day of life which involved incision of the imperforate hymen and drainage of the hematometrocolpos, followed by a cystovaginoscopy which was normal. She was discharged home the following day. A repeat abdominal ultrasound scan was performed at three months of age, showing no recurrence (Figure 1C). The pre-pubertal uterus was normal with no fluid seen, as were the ovaries and bladder.