Introduction
Clues about sarcoma pathogenesis
Sarcomas with specific reciprocal translocations
Sarcomas with specific somatic mutations
Sarcomas with more or less specific amplifications
Sarcomas with nonspecific complex karyotypes
Classification of sarcomas
Use of specific molecular changes in differential diagnosis
Histochemical staining | Immunohistochemistry | Molecular diagnostics | |
---|---|---|---|
Ewing sarcoma/PNET | PAS positive | CD99+ | Translocation EWSR1 |
Neuroblastoma | – | CD99−, CD56+ | MYCN amplification |
Alveolar rhabdomyosarcoma | – | MYF4 (myogenin)+, Desmin+ | Translocation FKHR (FOXO1A) |
Non-Hodgkin lymphoma/leukemia | PAS negative | CD45+ | Depending on subtype |
Small cell carcinoma | – | Keratin+, neuroendocrine markers | – |
(Poorly differentiated) synovial sarcoma | – | CD99+, BCL-2+ | Translocation SS18 (SYT) |
Small cell osteosarcoma | Deposition of bone (alkaline phosphatase) | – | – |
Mesenchymal chondrosarcoma | Deposition of cartilage | – | – |
Desmoplastic small round cell tumor | – | Coexpression keratin and desmin | Translocation EWSR1 |
Melanoma | – | Melanocytic markers+ | – |
Histochemical stainings | Immunohistochemistry | Molecular diagnostics | |
---|---|---|---|
Monophasic synovial sarcoma | – | EMA+, keratin+ | Translocation SS18 (SYT) |
Leiomyosarcoma | – | Smooth muscle markers+ | – |
Solitary fibrous tumor | – | CD34+ | – |
MPNST | Reticulin staining | S100 protein in a subset of cases | – |
Clear cell sarcoma | – | Melanocytic markers+ | Translocation EWSR1 |
GIST | – | CD117+, DOG1+ | KIT/PDGFRA mutation |
Dedifferentiated liposarcoma | – | MDM2, CDK4 over expression | MDM2 amplification |