Imaging of Fetal Head and Neck Masses: A Systematic and Anatomic Approach

Abstract

Congenital neck masses are rare lesions typically encountered during second-trimester anatomy ultrasound. Accurate diagnosis is crucial to appropriate ante- and perinatal management though imaging characterization remains a challenge. Ultrasound and MRI play complementary roles in the diagnosis of prenatal head and neck masses now facilitated by the increased availability of fetal MRI, technologic advancements in both imaging modalities and large tertiary referral centers with specialized care teams. As in both adult and pediatric head and neck imaging, a solid understanding of the neck anatomic spaces is a requisite to formulate a focused differential diagnosis. In this review, the more common fetal neck masses in four anatomic locations are presented. Unlike the wide spectrum of potential pathologies encountered in children, fetal neck masses can be categorized into three major groups: tumors, vascular malformations, and congenital lesions. Using an anatomic and systematic approach, the radiologist can narrow the differential diagnosis into a single or a limited list of possibilities. This article provides a focused review of the more common fetal head and neck pathologies, emphasizing their location and imaging characteristics. Based on these features, a reasonable differential diagnosis can be formulated and applied to prenatal counseling, delivery management, and postnatal treatment.