LAUSR

Alveolar soft part sarcoma (ASPS) is a rare soft tissue sarcoma (STS) mainly affecting adolescents and young adults. Its occurrence rate is approximately 0.5% to 0.9% of all STS cases. In children, the tumor most commonly occurs at the head and neck regions, especially in the orbit and tongue. Conversely, the lower extremities are the most common site of origin in adult patients. Although ASPS usually increases gradually, early metastasis is one of the tumor characteristics, which leads to decreased survival rate. Indeed, recent analysis reported that the 5-year overall survival was 27% for patients with distant metastasis but 82% for patients with locoregional disease. Histopathologically, an organoid or uniform nesting pattern is the most common characteristic feature of ASPS. The nests are separated through delicate partitions of connective tissues lined by flattened endothelium that form the pseudo-alveolar pattern, which is the source of the name of “alveolar” in ASPS. The tumor has high vascularity; therefore, contrastenhanced computed tomography (CT) image or magnetic resonance imaging (MRI) is very useful for the diagnosis. Radical resection is the standard treatment for ASPS. There