Lipoblastoma and lipoblastomatosis are benign tumors of embryonal adipocytes. While lipoblastomas present as solitary, well-circumscribed nodules or tumors (see lipoblastoma), lipoblastomatosis presents as ill-defined, diffusely infiltrating plaques. Slow growth is usual, but occasionally, lipoblastomatosis with rapid growth is seen. Most patients present before the age of 3, and males are more commonly affected. Lipoblastomatosis may be present at birth and it develops only rarely after the age of 10.

Lipoblastomatosis is most commonly found in the soft tissue of the extremities, including the axilla, shoulders, elbow, and hands. Involvement of the face, neck, buttocks, and mediastinum have also been reported. Patients can be asymptomatic or develop symptoms based on affected structures and organs.