title: YAP1-TFE3 epithelioid hemangioendothelioma: a case without vasoformation and a new transcript variant.
abstract: Epithelioid hemangioendothelioma is a rare vascular tumor of borderline malignancy characterized by recurrent WWTR1-CAMTA1 gene fusions in approximately 90 % of cases. In addition, a recurrent YAP1-TFE3 gene fusion has been identified in WWTR1-CAMTA1 negative epithelioid hemangioendotheliomas. This subset has been reported as having a distinct morphology with more obvious vasoformation, voluminous eosinophilic cytoplasm, and TFE3 positivity on immunohistochemistry. We report a case of a YAP1-TFE3 translocated epithelioid hemangioendothelioma arising in a groin lymph node in a 29-year-old male. Plump spindle cell morphology and absence of vasoformation made correct diagnosis particularly difficult. Immunohistochemistry showed nuclear positivity for both ERG and TFE3, fluorescence in situ hybridization showed break apart for TFE3 and RT-PCR identified a YAP1 exon1 to TFE3 exon 6 transcript, a previously unreported fusion variant. Awareness of this solid morphology and variant fusion will aid in identification of future cases of this rare vascular tumor.
authors: Department of Musculoskeletal Pathology, Royal Orthopaedic Hospital NHS Foundation Trust, Birmingham, UK, florian.puls@nhs.net.
authors: Florian
authors: F
authors: Puls
authors: Angela
authors: A
authors: Niblett
authors: Jade
authors: J
authors: Clarke
authors: Lars-Gunnar
authors: LG
authors: Kindblom
authors: Tom
authors: T
authors: McCulloch
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics*; D000328:Adult; D001483:Base Sequence; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors / Q000235:genetics*; D003550:Cystic Fibrosis / Q000150:complications; D018323:Hemangioendothelioma, Epithelioid / Q000235:genetics* / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D016040:Lung Transplantation; D008198:Lymph Nodes / Q000473:pathology; D008297:Male; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D010750:Phosphoproteins / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014157:Transcription Factors; D014178:Translocation, Genetic; D000091102:YAP-Signaling Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051778:Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; D015514:Oncogene Proteins, Fusion; D010750:Phosphoproteins; C069203:TFE3 protein, human; D014157:Transcription Factors; D000091102:YAP-Signaling Proteins; C088374:YAP1 protein, human