he collaborative guidelines endorsed by the American College of Obstetricians and Gynecologists, American College of Radiology, and American Institute of Ultrasound in Medicine for second-and third-trimester obstetric sonographic examinations 1 do not address fetal neck masses, which are rare congenital anomalies. However, when examining the fetal head and cervical spine regions, such masses tend to be large and are often readily apparent. The differential diagnoses include cystic hygroma, teratoma, goiter, lymphangioma, sarcoma, cervical myelomeningocele, and occipital encephalocele. [2][3][4] Fetal neck masses can be associated with aneuploidy, such as Turner syndrome (XO), or specific syndromes, such as Klippel-Trenaunay-Weber syndrome. 5 These masses can result in prenatal complications, including nonimmune hydrops and polyhydramnios. 3,5,6 Fetal neck masses can also complicate vaginal delivery as well as cause respiratory distress in the neonate and subsequent difficulty maintaining the airway. 5 Cervical teratomas and hemangiomas may result in high-output cardiac failure in the infant. 7,8 Therefore, after the in utero detection of a neck abnormality, narrowing the differential diagnosis, although potenMegan C. Kaplan, MD, Beverly G. Coleman, MD, Sara D. Shaylor, MD, Lori J. Howell, RN, MS, Edward R. Oliver, MD, PhD, Steven C. Horii, MD, N. Scott Adzick, MD Received June 21, 2012,
CASE SERIESThe purpose of this series is to describe the grayscale and color Doppler sonographic characteristics as well as the histopathologic features of rare solid posterior neck masses identified on prenatal sonography in pregnant patients. We conducted a retrospective review of detailed fetal sonographic examinations of second-and third-trimester pregnancies referred to the Center for Fetal Diagnosis and Treatment at the Children's Hospital of Philadelphia for suspected fetal neck masses from June 1998 to December 2011. Eight predominately solid posterior neck masses were identified on 139 studies performed during the study period. Of the 7 cases in which follow-up was available, 6 were confirmed as hemangiomas, and 1 was confirmed as a kaposiform hemangioendothelioma with Kasabach-Merritt syndrome. The most common sonographic features were hypervascularity (7) and calcifications (5). Posterior solid fetal neck masses are rare anomalies. Hemangioma is the most common etiology and should be suggested as the likely diagnosis rather than teratoma, even in the presence of calcifications.