Lipoblastoma is a type of subcuntaneous benign fatty tumor, which is exclusive to infants and children. These lesions are asymptomatic, and in most cases diagnosed within the first 3 years of life. The features of Lipoblastomas are a soft tissue mass with pseudofluctation( feels like liquid), nontender, with a lobulated surface. Lipoblastoma is generally a painless mass. Two forms are described. Form 1 is called superficial, also known as embryonal or fetal lipoma, which is a slow growing lesion. Form 2 is called diffuse, or Lipoblastomatosis, which is where a diffuse lesion arises in the skeletal muscle, retroperitoneum, or mesentry.
Lipoblastomas have 4 sub classifications:
- The class type, composed of minimal amount of myxoid component consosting of intercellular mucin, spindle cells, and and stellate primitive mesenchymal cells together with adipocytic component.
- Myxoid lipoblastomas, more than 50% is composed of interstitial mucin.
- Lipoma-like lipoblastomas, lacks a myxoid component and is instead composed of mature adipocytes with scattered monovaculoated & multicuolated lipoblasts.
- Hibernoma-like lipoblastomas, lacks a myxoid component and is composed of multivacuolated lipoblasts.
The lesions usually occur in the subcutis of upper and lower extremities. The tumor presents itself as a soft, lobulated, encapsulated mass with a tan yellow to white cut surface. The preferred treatment is excision. The diffuse form is very difficult to excise completely, which could lead to another recurrence. Recurrence has been reported in 25% of cases.