Table 3.
Immunohistochemistry of selected retroperitoneal mesenchymal tumors.
| Liposarcoma (Well-Differentiated/Dedifferentiated) | Solitary Fibrous Tumor | Inflammatory Myofibroblastic Tumor | Leiomyosarcoma | MPNST | Synovial Sarcoma | DSRCT | PEComa | Extraskeletal Ewing Sarcoma | |
|---|---|---|---|---|---|---|---|---|---|
| SMA | − (a) | +/− | +/− | + | − | − | − | + | − |
| Desmin | − (a) | − | +/− | + | − | − | + | +/− | − |
| CD34 | − | + | +/− | − | + | − | − | − | − |
| S100 protein | +/− | − | − | − | + | +/− | − | +/− | +/− |
| MDM2 | + | − | − | − | − (e) | − | − | − | − |
| CDK4 | + | − | − | − | − | − | − | − | − |
| STAT6 | − (b) | + (d) | − | − | − | − | − | − | − |
| ALK | − | − | + | − | − (f) | − | − | − | − |
| CD99 | − | + | − | − | − | + | + | − | + |
| H3K27me3 | Retained (c) | Retained | NA | Retained | Loss (g) | Retained (h) | NA | NA | Retained |
| NKX2.2 | − | − | − | − | − | − (i) | − (j) | − | + |
| TLE1 | − | +/− | − | − | +/− | + | − | − | − |
| SOX10 | − | − | − | − | + | − | − | − | − |
| WT1 | − | − | − | − | − | − | + | − | − |
| HMB-45, melan-A | − | − | − | − | − | − | − | + | − |
| Cytokeratin, EMA | − | +/− | +/− | +/− | − | + | + | − | +/− |
MPNST, malignant peripheral nerve sheath tumor; DSRCT, desmoplastic small round cell tumor; PEComa, perivascular epithelioid cell tumor; +, positive staining; +/−, focal or variable staining; −, negative staining; NA, no available data; (a) can be expressed in well-differentiated and dedifferentiated liposarcoma, (b) may be expressed in a subset of dedifferentiated liposarcoma, (c) may be lost in a subset of dedifferentiated liposarcoma, (d) may be decreased or lost in dedifferentiated solitary fibrous tumor, (e) can be overexpressed in a subset of MPNST, (f) may be expressed in a subset of MPNST, (g) lost in approximately 50% of MPNSTs (in 90% of high-grade MPNSTs), (h) may be lost in a subset of synovial sarcoma, (i) may be expressed in a subset of poorly differentiated synovial sarcoma, (j) may be expressed in a subset of DSRCT.