Proximal Type Epithelioid Sarcoma
Proximal Type Epithelioid Sarcoma
Supplemental Studies
Immunohistology
- Keratin 95%
- Low molecular weight keratin CK8 is positive in 95%
- High molecular weight keratins rare to 50%
- CK7 22% and CK20 0-15%
- EMA 95%
- INI1 loss in 95%
- CA125 positive, probably 90% (few proximal cases tested)
- CD34 50%
- Vimentin >95%
- Actin (MSA or SMA) 30-40%
- Desmin 15-70%
- Higher rate of desmin reactivity reported in proximal type disease
- S100 rare
- CD31 negative (rare cytoplasmic)
- Factor VIII negative
Genetic study
- Loss of heterozygosity on chromosome 22 has been detected in some cases
