Fetal for Wednesday, June 3rd, 2026

Contributed by CHU de Québec (CHUL)
Marie-Hélène Paul, and Guylaine Gleeton.

History

A 28-year-old multigravida was referred to our department for the evaluation of a fetal abdominal cyst detected incidentally at 28 +5 weeks. During the first trimester examination, the nucal translucency was normal. A fetal morphological ultrasound performed at 26 weeks revealed left renal pelvis ectasia (4,6 mm) with hydroureter. The ultrasound performed at 28 weeks in our institution revealed bilateral hydronephrosis, ascites, bladder dilatation and a retro vesical mass.

Images (Click any image to enlarge)

Fetal US showing an anechoic cystic retro vesical mass.
Sagittal T2 HASTE images showing a pelvic mass posterior to the bladder and anterior to the rectum with high T2 content corresponding to fluid.
Axial T2 HASTE
Coronal T2 HASTE

Question

What is the diagnosis?

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Correct answer

Hydrometrocolpos

Discussion

Hydrometrocolpos is a rare congenital condition (0,006%) in which the uterus and vagina are distended by retained fluid other than blood. It occurs secondary to a combination of stimulated secretions as well as distal vaginal obstruction. Various obstructive vaginal anomalies can be found, such as imperforate hymen, transverse vaginal septum, vaginal atresia and malformations of cloaca including urogenital sinus.

Urinary tract obstruction as in this case is one of the complications of congenital hydrometrocolpos. Others are renal failure, repeated urinary tract infections, rupture and peritonitis. Urinary tract obstruction can lead to oligohydramnios antenatally.

Differential diagnosis

Hydrometrocolpos may be misidentified as an abdominal cystic mass. Possible differential diagnoses include ovarian cyst, duplication cyst, mesenteric cyst, meconium cyst, urachal cyst, anterior meningocele, and a pelvic component of sacrococcygeal teratoma.

References

  • Spencer R, Levy DM. Hydrometrocolpos: report of three cases and review of the literature. Ann Surg. 1962;155(4):558–571. doi: 10.1097/00000658-196204000-00013. Tanitame K, Tanitame N, Urayama S, Ohtsu K. Congenital anomalies causing hemato/hydrocolpos: imaging findings, treatments, and outcomes. Jpn J Radiol. 2021 Aug;39(8):733-740. doi: 10.1007/s11604-021-01115-7. Epub 2021 Apr 11. PMID: 33840015; PMCID: PMC8338850. Bannour B, Abbassi H, Guerbej E, Bannour I, Boughizane S. Prenatal diagnosis of isolated fetal hydrometrocolpos: A case report. Radiol Case Rep. 2024 Sep 23;19(12):6147-6151. doi: 10.1016/j.radcr.2024.08.150. PMID: 39376953; PMCID: PMC11456795. Nagaraj BR, Basavalingu D, Paramesh VM, Nagendra PD. Radiological Diagnosis of Neonatal Hydrometrocolpos- A Case Report. J Clin Diagn Res. 2016 Mar;10(3):TD18-9. doi: 10.7860/JCDR/2016/18537.7510. Epub 2016 Mar 1. PMID: 27134971; PMCID: PMC4843356.