Malignant chondroid syringoma is genetically related to tumors with PHF1 rearrangements such as low-grade endometrial sarcoma and ossifying fibromyxoid tumor, but also with tumors having TFE3 rearrangements such as renal cell carcinoma, alveolar soft part sarcoma, PEComa, and epithelioid hemangioendothelioma.
Patients with conventional epithelioid hemangioendothelioma with WWTR1-CAMTA1 fusion had a less favorable outcome compared with the YAP1-TFE3 subset, the 5-year overall survival being 59% versus 86%, respectively.
We point out the telltale immunophenotypes: angiolymphoid hyperplasia with eosinophilia and EH (FOS-B/others negative), PM-HAE (FOS-B/AE1/AE3/others negative), epithelioid hemangioendothelioma (CAMTA-1 or TFE-3/others negative).
Care should be taken to identify such cells in limited biopsies; immunohistochemistry for CAMTA1, a specific and sensitive marker for EHE, can be confirmatory.
A WWTR1-CAMTA1 fusion is present in most classic epithelioid hemangioendothelioma, regardless of their clinical behavior, suggesting that additional genetic abnormalities might be responsible in driving a more aggressive biology.
A WWTR1-CAMTA1 fusion is present in most classic epithelioid hemangioendothelioma, regardless of their clinical behavior, suggesting that additional genetic abnormalities might be responsible in driving a more aggressive biology.
Characterization of the genetics of EHE is important because targeted therapies toward products of the specific WWTR1-CAMTA1 gene fusion may have an impact in the near future.
Characterization of the genetics of EHE is important because targeted therapies toward products of the specific WWTR1-CAMTA1 gene fusion may have an impact in the near future.
The 10% of EHEs that lack the TAZ⁻CAMTA1 fusion instead have a fusion of Yes-associated Protein (YAP) and Transcription Factor E3 (TFE3) genes (YAP-TFE3).
The 10% of EHEs that lack the TAZ⁻CAMTA1 fusion instead have a fusion of Yes-associated Protein (YAP) and Transcription Factor E3 (TFE3) genes (YAP-TFE3).
A recurrent YAP1-TFE3 gene fusion has been identified in WWTR1-CAMTA1-negative epithelioid hemangioendotheliomas arising in soft tissue, bone, and lung, but not in liver.
A recurrent YAP1-TFE3 gene fusion has been identified in WWTR1-CAMTA1-negative epithelioid hemangioendotheliomas arising in soft tissue, bone, and lung, but not in liver.
Genetic studies also led to the finding that WWTR1-CAMTA1 fusions are useful diagnostic markers for epithelioid hemangioendotheliomas, which can present as pleural-based masses.
Genetic characterization of several soft tissue tumour types that occur in the skin has resulted in the identification of diagnostically useful markers: ALK gene rearrangement with corresponding ALK protein expression by immunohistochemistry in epithelioid fibrous histiocytoma; the WWTR1-CAMTA1 fusion gene with CAMTA1 protein expression in epithelioid haemangioendothelioma; MYC amplification and overexpression in radiation-associated angiosarcoma; and EWSR1 gene rearrangement in cutaneous myoepithelial tumours.
Genetic characterization of several soft tissue tumour types that occur in the skin has resulted in the identification of diagnostically useful markers: ALK gene rearrangement with corresponding ALK protein expression by immunohistochemistry in epithelioid fibrous histiocytoma; the WWTR1-CAMTA1 fusion gene with CAMTA1 protein expression in epithelioid haemangioendothelioma; MYC amplification and overexpression in radiation-associated angiosarcoma; and EWSR1 gene rearrangement in cutaneous myoepithelial tumours.
Genetic studies also led to the finding that WWTR1-CAMTA1 fusions are useful diagnostic markers for epithelioid hemangioendotheliomas, which can present as pleural-based masses.
Interestingly, we observed CAMTA1 gene break-apart in all of the five TFE3-positive EHEs via FISH assays, and four out of the five TFE3-positive EHEs exhibited WWTR1-CAMTA1 gene fusions via RT-PCR.
Interestingly, we observed CAMTA1 gene break-apart in all of the five TFE3-positive EHEs via FISH assays, and four out of the five TFE3-positive EHEs exhibited WWTR1-CAMTA1 gene fusions via RT-PCR.