Table 2 Summary of immunohistochemistry and molecular characteristics of cutaneous epithelioid soft tissue tumors
Immunohistochemistry | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Most commonly altered gene or translocation | Cytokeratins | CD34 | S100/SOX10 | INI-1 | HMB45/ MelanA | Smooth muscle actin | Desmin | CD31/ERG | NKI/C3 | Other often positive markers | ||
Epithelioid fibrous and fibrohistiocytic tumors | Epithelioid fibrous histiocytoma | ALK | − | − | − | Retained | − | − | − | − | − | ALK, EMA |
Cellular neurothekeoma | – | – | – | Retained | − | +/ – | − | – | + | PGP9.5, MiTF, CD10 | ||
Epithelioid fibrous papule | – | − | – | Retained | − | − | – | – | − | − | ||
Epithelioid peripheral nerve sheath tumors | Epithelioid Schwannoma | SMARCB1 (~50%) | – | − | +(diffuse) | Lost in a subset | − | − | − | − | − | − |
Epithelioid malignant peripheral nerve sheath tumor | SMARCB1 | – | – | +(diffuse) | Lost in a majority | − | − | − | − | − | − | |
Epithelioid tumors with myoid or myoepithelial differentiation | Cutaneous syncytial myoepithelioma | EWSR1 | – | – | + | Retained | − | +/– | – | – | – | EMA |
Mixed tumor | PLAG1 | + | − | + | Retained | − | +/− | − | – | − | EMA, p63, GFAP | |
Soft tissue myoepithelioma | EWSR1(~45%) | + | − | + | Retained | − | +/− | − | – | – | EMA, p63, GFAP | |
Myoepithelial carcinoma | EWSR1 | + | − | +S100/Rare + SOX10 | Lost in a subset (~50%) | − | +/− | − | – | – | – | |
Perivascular epithelioid cell tumor (PEComa) | mTOR pathway (unknown gene) | − | − | − | Retained | + | + | + | − | + | MiTF | |
Epithelioid vascular tumors | Epithelioid hemangioma | Rare | + | − | Retained | − | + (pericytes) | − | + | − | D2-40, rare EMA | |
Cutaneous epithelioid angiomatous nodule | − | + | − | Retained | − | + (pericytes) | – | + | – | − | ||
Epithelioid hemangioendothelioma | WWTR1-CAMTA1 | + (20–30%) | + | − | Retained | − | + | – | + | − | CAMTA1, CAM5.2 | |
Epithelioid sarcoma-like (pseudomyogenic) Hemangioendothelioma | FOSB-SERPINE1 | + | − | − | Retained | − | Rarely focal and weak | – | ERG+, CD31 (50%) | − | FOSB | |
Epithelioid angiosarcoma | MYC in radiation- and lymphedema-associated cases | +/− (focal) | +/– | − | Retained | – | − | − | + | − | EMA, MYC (in radiation- & lymphedema- associated cases) | |
Other malignant epithelioid tumors | Epithelioid sarcoma | SMARCB1 | + | +/− | − | Lost | – | − | − | +/− | − | − |
Clear cell sarcoma | EWSR1-ATF1 | – | – | + | Retained | + | − | − | − | + | − | |
