What are abnormal growths that usually appear on a baby's neck or head known as?

Cystic hygromas are abnormal growths characterized by fluid-filled sacs that typically appear on a baby's neck or head, often as a result of a lymphatic system anomaly. These growths are soft, compressible, and can vary in size. Cystic hygromas are most commonly diagnosed in neonates and infants and may be associated with genetic syndromes or chromosomal abnormalities. Their presence can lead to complications due to the location, including respiratory difficulties if they obstruct the airway.

In contrast, hemangiomas are benign tumors made up of blood vessels that usually appear on the skin and can be found anywhere on the body, but they are distinct from cystic hygromas in both composition and appearance. Teratomas are germ cell tumors that can contain various tissue types, including hair, muscle, and bone, and are often found in the sacrococcygeal region or other sites rather than solely the neck or head. Nevi refer to moles or pigmented lesions on the skin and do not share the same fluid-filled characteristics or presentation as cystic hygromas. Thus, identifying cystic hygromas correctly reflects an understanding of the specific nature and implications of these growths in neonatal care.