Benign Structures Mimicking Right Atrial Masses on Prenatal Ultrasound

Abstract

Advances in imaging have resulted in more frequent reporting of primitive right atrial structures which can sometimes mimic cardiac tumors in prenatal ultrasound. Prominent crista terminalis and Chiari network are examples of these structures. We describe two cases of pregnant women referred to the fetal cardiology clinic for fetal echocardiography for right atrial masses seen on prenatal ultrasound suspicious of tuberous sclerosis. The first case subsequently diagnosed as crista terminalis and the second case as a prominent Chiari network. Postnatal ECHO confirmed the benign nature of these structures. It is important to differentiate tumors from prominent benign structures in the right atrium in fetal ECHO. The location and the similar echogenicity to the adjacent atrial tissue are clues for differentiation of these structures from atrial tumors.

Prominent crista terminalis mimicking a right atrial mass: a systematic literature review and meta-analysis

“…It results from regression of the septum spurium and is formed from the fusion of right angle of the venous sinus, the superior inferior vena cava, and the original atrium during fetal life (1,2). Interestingly, so far there have been three cases reporting prominent crista terminalis found in the fetus and confirmed in the neonatal period (3)(4)(5). Anatomically, the crista terminalis is a semilunar-shaped smooth muscular structure, which divides the RA into a lateral and medial part.…”