Prenatal Detection of a Right Atrial Echogenic Mass - A Case Report of Hypertrophic Crista Terminalis

Sep 30, 2026

Hypertrophic or prominent crista terminalis (HCT) is a normal fibromuscular ridge in the right atrium that can resemble an intracardiac mass on prenatal ultrasound or echocardiography. A fetal right atrial echogenic mass was detected at 32 weeks and remained stable throughout gestation. Postnatally it was confirmed as likely HCT. No hemodynamic compromise, growth, or pathological sequelae were observed, supporting conservative recognition and management.

LanguageEnglish

CategoryHealthcare

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Reading Time23 min

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Case Report Prenatal Detection of a Right Atrial Echogenic Mass: A Case Report of Hypertrophic Crista Terminalis Mariangela Pati 1, Maria Paola Bonasoni 2, *, Andrea Musarò 1, Benedetta Petrachi 1, Francesco Di Dio 3, Elena Chesi 3, Francesco Leo 3, Giulia Barbato 3, Sonia Ricò 3, Giancarlo Gargano 3, Khush Shah 4 and Lorenzo Aguzzoli 1 Academic Editor: Dah Ching Ding Received: 14 November 2025 Revised: 11 December 2025 Accepted: 18 December 2025 Published: 20 December 2025 Copyright: © 2025 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license. 1 Unit of Obstetrics and Gynecologic Oncology, Azienda USL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy; [mariangela.pati@ausl.re.it](mariangela.pati@ausl.re.it) (M.P.); [andrea.musaro@ausl.re.it](andrea.musaro@ausl.re.it) (A.M.); [benedetta.petrachi@ausl.re.it](benedetta.petrachi@ausl.re.it) (B.P.); [lorenzo.aguzzoli@ausl.re.it](lorenzo.aguzzoli@ausl.re.it) (L.A.) 2 Pathology Unit, Azienda USL-IRCCS di Reggio Emilia, 42122 Reggio Emilia, Italy 3 Neonatal Intensive Care Unit, Azienda USL-IRCCS di Reggio Emilia, Via Amendola 2, 42122 Reggio Emilia, Italy; [francesco.didio@ausl.re.it](francesco.didio@ausl.re.it) (F.D.D.); [elena.chesi@ausl.re.it](elena.chesi@ausl.re.it) (E.C.); [francesco.leo@ausl.re.it](francesco.leo@ausl.re.it) (F.L.); [giulia.barbato@ausl.re.it](giulia.barbato@ausl.re.it) (G.B.); [sonia.rico@ausl.re.it](sonia.rico@ausl.re.it) (S.R.); [giancarlo.gargano@ausl.re.it](giancarlo.gargano@ausl.re.it) (G.G.) 4 Department of Medicine, Lake Erie College of Osteopathic Medicine at Seton Hill, Greensburg, PA 15601, USA; [ksshah0318@gmail.com](ksshah0318@gmail.com) * [Correspondence: paolabonasoni@yahoo.it](Correspondence: paolabonasoni@yahoo.it) Abstract Background and Clinical Significance: The crista terminalis (CT) is a fibromuscular ridge located on the posterolateral wall of the right atrium, formed by the junction of the sinus venosus and the primitive right atrium. A hypertrophic or prominent CT (HCT) refers to a thickened or conspicuous configuration of this normal anatomical structure. In prenatal ultrasound (US) and/or echocardiographic assessments, HCT can mimic a right atrial mass, such as a tumor or a thrombus. Case Presentation: Herein, we describe a case of a fetal right atrial echogenic mass detected at 32 weeks, which remained stable through gestation and was confirmed postnatally as a likely HCT. No hemodynamic compromise, growth, or pathological sequelae were observed. Conclusions: Our case reinforces the importance of including atrial structural variants in the differential diagnosis of intracardiac masses, particularly when features favor stability and low risk. Serial imaging, avoidance of premature invasive measures, and careful counseling are key to appropriate management. Keywords: hypetrophic crista terminalis (HCT); prenatal ultrasound (US); echocardiography 1. Introduction The crista terminalis (CT) is a fibromuscular ridge located on the posterolateral wall of the right atrium, formed by the junction of the sinus venosus and the primitive right atrium [1,2] . Embryologically, the CT develops from the regression of the septum spurium and the fusion of the venous sinus, superior and inferior vena cava (SVC and IVC), and the original atrium during fetal development. This structure divides the right atrium into lateral and medial compartments and serves as the junction between the smooth-walled sinus venosus and the trabeculated right atrial appendage [1] . The CT is composed of working myocardial cells, pacemaker cells, and transitional cells, and functions as a critical zone for internodal conduction. Its high collagen content can contribute to slowed conduction, and age-related remodeling may be associated with abnormal conduction properties. The CT is recognized as a substrat

FAQs

Why can hypertrophic crista terminalis mimic a right atrial mass during prenatal imaging?

Because HCT can appear as an echogenic structure in the same region and with similar echogenicity to adjacent myocardium, it may be mistaken for a tumor or thrombus on ultrasound or echocardiography.

What was observed in the presented case from prenatal diagnosis to postnatal confirmation?

A fetal right atrial echogenic mass was identified at 32 weeks, stayed stable through gestation, and was confirmed postnatally as likely HCT.

What management approach does the case emphasize to reduce unnecessary interventions?

It highlights the importance of including atrial structural variants in differential diagnosis, using serial imaging, avoiding premature invasive measures, and providing careful counseling when features suggest stability and low risk.

Sep 30, 2026

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