What describes a cystic hygroma?

A cystic hygroma is best described as a fluid-filled structure that typically occurs in the neck region. It is a congenital lymphatic malformation, characterized by the accumulation of lymphatic fluid, resulting in a cyst-like swelling. This condition is primarily caused by an abnormal development of the lymphatic system, which can lead to large, soft, and compressible masses filled with clear fluid.

In the context of cystic hygromas, they most commonly present as swollen areas on the neck or head, but they can also be found axillary (in the armpit) or in other regions of the body. The presence of fluid is a key aspect, distinguishing it from solid masses or abnormal growths.

Other options mischaracterize the condition. For instance, a solid mass on the neck lacks the defining characteristic of fluid accumulation, while abnormalities in the abdomen or bone deformities do not relate to the lymphatic system's function in the same manner as cystic hygromas. Understanding these details helps clarify why recognizing the cystic component of the hygroma is crucial in determining its nature and implications in clinical practice.