The histogenesis of ASPS remains incompletely understood, but the entity is now molecularly defined by a recurrent unbalanced translocation der(17)t(X;17)(p11;q25) resulting in ASPSCR1-TFE3 fusion, activating the MET proto-oncogene signaling pathway [6–8]. This evidence concerns the gene TFE3 and alveolar soft part sarcoma.