TLE1 immunohistochemical staining was positive in 82% of synovial sarcomas compared to only 15% of MPNSTs and 8% of SFTs, demonstrating it is a sensitive and specific marker for synovial sarcoma.
Observational (n=212)
Does immunohistochemical staining for TLE1 distinguish synovial sarcoma from histologic mimics?
TLE1 is a sensitive and specific immunohistochemical marker that can effectively distinguish synovial sarcoma from other mesenchymal tumors in differential diagnosis.
Transducer-like enhancer of split 1 (TLE1) is overexpressed in synovial sarcomas. We investigated TLE1 expression by immunohistochemical analysis in a well-characterized series of synovial sarcomas and other mesenchymal tumors most commonly considered in the differential diagnosis. Whole tissue sections of 212 tumors were evaluated: 73 synovial sarcomas (23 biphasic, 28 monophasic, 22 poorly differentiated), 47 malignant peripheral nerve sheath tumors (MPNSTs), 49 solitary fibrous tumors (SFTs), 20 fibrosarcomatous variants of dermatofibrosarcoma protuberans, and 23 Ewing sarcomas/primitive neuroectodermal tumors (PNETs). All monophasic and poorly differentiated SSs and Ewing sarcoma/PNETs were previously confirmed to harbor t(X;18) and EWSR1 gene rearrangements, respectively. In total, 60 (82%) of 73 synovial sarcomas were positive for TLE1, including 18 biphasic (78%), 22 monophasic (79%), and 20 poorly differentiated (91%) tumors. Of the other tumors, only 7 MPNSTs (15%) and 4 SFTs (8%) were positive for TLE1, most of which showed only weak staining. TLE1 is a sensitive and specific marker for synovial sarcoma and can be helpful to distinguish synovial sarcoma from histologic mimics, particularly if moderate or strong staining is observed. In this study, only a small subset of MPNSTs and SFTs showed limited staining for TLE1.
Foo et al. (Fri,) conducted a observational in Synovial sarcoma and histologic mimics (n=212). TLE1 immunohistochemical staining vs. Histologic mimics (MPNSTs, SFTs, dermatofibrosarcoma protuberans, Ewing sarcomas/PNETs) was evaluated on TLE1 positivity. TLE1 immunohistochemical staining was positive in 82% of synovial sarcomas compared to only 15% of MPNSTs and 8% of SFTs, demonstrating it is a sensitive and specific marker for synovial sarcoma.