Spindle cell liposarcoma with a TRIO-TERT fusion transcript.

Conventional well-differentiated, dedifferentiated, and myxoid liposarcomas have long been known to harbor numerous typical genetic alterations that allow for diagnosis of these tumors. These include MDM2 and CDK4 amplification in well-differentiated and dedifferentiated liposarcomas as well as FUS-DDIT3 rearrangements in myxoid liposarcoma. More recently, in-frame TRIO-TERT fusion genes have been described in a subset of non-translocation-related sarcomas including myxofibrosarcoma, dedifferentiated liposarcoma, undifferentiated pleomorphic sarcoma, pleomorphic rhabdomyosarcoma, and leiomyosarcoma. These genetic rearrangements lead to TERT mRNA expression levels hundreds of times higher than normal, causing increased telomerase activation in these tumors. Herein, we describe an unusual case of a liposarcoma with spindle cell features and a TRIO-TERT fusion transcript identified through next-generation sequencing.