Alveolar Soft Part Sarcoma
Supplemental Studies
Immunohistology
- Muscle markers
| TFE3 |
100% positive |
| Desmin |
About 50% positive |
| Muscle specific actin |
Variable, occasional cases positive |
| Smooth muscle actin |
Variable, occasional cases positive |
| Myoglobin |
Variable, occasional cases positive |
| MyoD1 |
All recent reports negative |
- S100 variable, occasional cases positive
- HMB45 negative
- Keratin negative
- Chromogranin 1/5 positive
- TFE3 also stains Xp11 translocation renal cell carcinoma
- Focal and less intense reactions seen in melanoma, clear cell sarcoma, PEComa and angiomyolipoma
Genetic analysis
- Unbalanced translocation der(17)t(X;17)(p11.2;q25) present in all cases studied, produces TFE3-ASPL gene product.
- Detectable with two color break-apart FISH
- Identical fusion transcript resulting from a balanced translocation is found in translocation-associated renal carcinomas.
