A Case of a Chorionic Bump: New Sonographic-Histopathologic Findings With Review of the Literature

Chorionic bump: Progression to a subamniotic hematoma

INTRODUCTION

A chorionic bump is an increasingly recognized ultrasound finding in first-trimester scans, which has been associated with early pregnancy loss. In ongoing second-trimester pregnancies, however, chorionic bumps usually resolve over time with no deleterious effect on the fetus. In this report, we describe the incidental ultrasound detection of a chorionic bump in early pregnancy and its progression to a subamniotic hematoma in the second trimester of pregnancy that persisted as such until delivery.

CASE REPORT

A round, echogenic mass protruding from the choriodecidual surface measuring 13 × 11 × 8 mm was first identified during a transvaginal scan at 6.3 weeks' gestation. Subsequent follow-up scan at 8.3 weeks revealed an increase in the size of the chorionic bump to 25 × 20 × 19 mm, which remained stable as determined by the routine late first-trimester scan. At the second-trimester scan, a subamniotic hematoma was identified in the surface of the placenta, close to the insertion of the umbilical cord. Subsequently, the pregnancy proceeded uneventfully.

DISCUSSION

The etiopathology and clinical significance of a chorionic bump remain unclear. The case herein reported demonstrates that a chorionic bump can grow considerably without having a deleterious effect on the early embryo and, occasionally, can persist throughout pregnancy as a subamniotic hematoma.

CONCLUSION

A chorionic bump can occasionally progress to a subamniotic hematoma from the second trimester onwards. This observation further supports the hypothesis that a chorionic bump is the result of choriodecidual bleeding. An alternative explanation for the development of subamniotic hematomas is proposed.

Pregnancy and perinatal outcomes in pregnancy with diagnosis of chorionic bump on first-trimester sonography: a systematic review and meta-analysis

OBJECTIVE

To assess the relationship between the presence of the sonographic finding of chorionic bump (CB) during first trimester and miscarriage rate or other perinatal outcomes.

METHODS

PubMed, Medline, Embase, Cinahl and Clinicaltrials.gov databases, from inception to April 8, 2021 were explored utilizing combinations of the relevant medical subject heading (MeSH) terms, key words, and word variants for "CB" and "pregnancy." Prospective and retrospective case-control studies were eligible for inclusion. Odds ratios (ORs) comparing obstetrical outcomes among pregnancies with CB and normal pregnancies were determined with 95% confidence intervals (CI) using random-effects models. Primary outcome of interest was miscarriage rate. Secondary outcomes were: alive newborns (ANB) rate, adverse pregnancy outcomes (APO) and vaginal bleeding. Quality assessment of the included studies was performed using the Newcastle-Ottawa Scale.

RESULTS

Five studies including 173 pregnant women with CB (study group) and 1,263 pregnant women without CB (control group) were included. Pregnancies affected by CB resulted to be associated with a significantly higher miscarriage rate (43.3% vs 20.7%; OR 2.95 95% CI 2.02-4.31, p < .00001), and conversely with a significantly lower rate of ANB (60.3% vs 82%; OR 0.35 95% CI 0.20-0.63, p = .0004). In addition, the risk of APO was around three-fold higher in the study group (52.2% vs 4.12%; OR 2.98 95% CI 1.04-8.51, p = .04), while the rate of vaginal bleeding was higher in the study group, without reaching a statistical significance (48% vs 16.4%; OR 2.21 95% CI 0.64-7.65 p = .21).

DISCUSSION

The presence of CB at first trimester ultrasound significantly increases the risk of miscarriage and APO, and intact the rate of ANB. This article is protected by copyright. All rights reserved. Key message: The presence of CB on early first trimester ultrasound increases three-fold the risk of miscarriage and adverse pregnancy outcomes and reduces the rate of alive newborns. It is important to consider CB as an ultrasound marker that requires a close surveillance throughout pregnancy to prevent long-term complications and provide adequate counseling to the patient.

Chorionic Bump: Radiologic Features and Pregnancy Outcomes

Background

Chorionic bump is a rare condition defined as a bulge or protrusion from the choriodecidual surface into the gestational sac. The limited literature on this infrequent entity suggests that the pregnancies with multiple chorionic bumps mostly result in fetal demise.

Aims

To review the available literature and the patients from our institute having sonographic findings of chorionic bump and making the sonographers and radiologists aware of this known cause of first-trimester pregnancy loss.

Study design

A retrospective review of the cases diagnosed at our institute during the last four years.

Methods and materials

Single-center institutional data for four years (January 2016-December 2019) was accessed using ICD codes. IRB approval was waived owing to the anonymized use of patient data.

Results

Six female patients diagnosed with chorionic bump were included, with a mean age of 29.83±12 years. The average gestational age at the time of diagnosis was 8.16±3 weeks. The most common sonographic findings were a protrusion from the chorionic wall into the gestational sac cavity, having a central hypoechoic region with peripheral hyperechoic rim (isoechoic to the chorion) and having no vascularity (n=5), and the less common finding was a hyperechoic protrusion with no vascularity (n=1). n=5 had a single lesion, and n=1 had two lesions. The average diameter of the lesion in the largest dimension was 18±11 mm. n=3 pregnancies resulted in a first-trimester miscarriage, and n=3 pregnancies delivered healthy babies at term. 

Conclusions

A chorionic bump significantly increases the risk of a first-trimester miscarriage.

Chorionic bump at 11 to 13 weeks' gestation: Prevalence and clinical significance

OBJECTIVE

To gather additional data on pregnancy outcome when a chorionic bump is detected at the time of the 11- to 13-week scan.

METHODS

The presence of a chorionic bump was prospectively recorded in a database of women presenting for their first-trimester sonographic screening. Clinically relevant information was obtained by reviewing ultrasound reports and medical records or contacting the referring obstetrician or the parents themselves.

RESULTS

During a 4.5-year study period from June 2014 to December 2018, a chorionic bump was identified in 23 out of 3375 pregnancies, for a prevalence of 1/147 or 0.7%. All women were asymptomatic at the time of evaluation. The chorionic bump was single in 21 (91%) cases, located in the central part of the placenta in 17 (74%) cases, and the median largest diameter was 20 mm (range, 10-43). Although the placenta was low-lying in 14 (61%) cases, all but one patient had a normally located placenta at the midtrimester anatomy scan. With the exception of one pregnancy complicated with trisomy 21, the outcome was universally good.

CONCLUSION

Our experience suggests that a chorionic bump detected during the 11- to 13-week scan is usually a transient, is incidental finding, and probably has no clinical significance.

Chorionic bump in a pregnant patient with a history of infertility

Chorionic bump is a rare condition in the first trimester of pregnancy. It appears as a bulge from the choriodecidual surface into the gestational sac. So far, there have been no ultrasound or clinical markers that can predict a difference in outcomeWe report a case of a pregnant woman with history of infertility, diagnosed in the first trimester with a chorionic bump. It disappeared spontaneously at 23 weeks of gestation. The pregnancy went well and she delivered a healthy baby.The aetiology and clinical significance of the chorionic bump remains unclear.