Cystic hygromas in children: sonographic-pathologic correlation.

The sonographic findings in eight children with surgically proved cystic hygroma were reviewed and correlated with the pathologic specimens. Six tumors occurred in the neck, one occurred in the axilla, and one involved the soft tissues of the thigh, scrotum, and pelvis. A cystic hygroma characteristically appears as a multiloculated cystic mass with septa of variable thickness that contain solid components arising from the cyst wall or the septa. Correlation of the sonogram with the pathologic specimen demonstrated that the echogenic component corresponded to a cluster of abnormal lymphatic channels, too small to be resolved with ultrasound. Large lesions had ill-defined boundaries, with cystic components dissecting between normal tissue planes. Sonographically, one can usually differentiate these tumors from other cervical masses, especially soft-tissue hemangiomas. Sonography is also helpful in determining the extent of the lesion before surgery and in assessing postoperative complications and recurrences.