Superficial Atypical Lipomatous Tumor

**Semantic type:** Neoplastic Process

**Definition:** A locally aggressive mesenchymal neoplasm of a superficial body structure that is characterized by the presence of an adipocytic proliferation exhibiting at least focal nuclear atypia in both adipocytes and stromal cells. Amplification of MDM2 and/or CDK4 is almost always present.

**Synonyms:** - Superficial ALT - Superficial ALT/WDLPS - Superficial Atypical Lipomatous Tumor/Well Differentiated Liposarcoma - Superficial Atypical Lipomatous Tumor/Well-Differentiated Liposarcoma - Superficial Well Differentiated Liposarcoma - Superficial Well-Differentiated Liposarcoma - Superficial well differentiated liposarcoma - Well differentiated liposarcoma of superficial soft tissue