Background: Alveolar soft part sarcoma is a rare but highly malignant tumour and little is known about its radiologic pattern in children.
Objective: To describe the radiologic features of alveolar soft part sarcoma in children and adolescents.
Materials and methods: We retrospectively analysed the clinical and imaging data of six children age 7-17 years at diagnosis, with histologically or genetically proven alveolar soft part sarcoma.
Results: The tumours were located deep within muscles of the limbs (n = 4), in chest wall muscle (n = 1) and in the orbit (n = 1). High-flow feeding arteries, large drainage veins and intense enhancement were consistent findings by all imaging modalities. At MRI, all tumours demonstrated high signal intensity on T2-weighted images and high or iso-intense signal on T1-W imaging compared to muscle. In tumours larger than 70 mm in one dimension (n = 3/6), large vessels converging toward the tumour centre led to a highly vascularised central stellar area pattern. Five children demonstrated synchronous (n = 4/5) and metachronous (n = 1/5) lung metastases.
Conclusion: Alveolar soft part sarcoma should be suggested when a highly vascularised, intramuscular mass demonstrating large feeding and drainage vessels converging toward a central stellar area is seen in children, especially if synchronous lung metastases are present.