Abstract
Aims: Epithelioid haemangioendothelioma (EHE) is a malignant vascular neoplasm. Subsets have been characterized previously by translocations resulting in either WWTR1-CAMTA1 or YAP1-TFE3 fusion. We sought to develop molecular and immunohistochemical (IHC) assays to aid in the diagnosis and characterization of EHE. Methods and results: Fifty-two formalin-fixed, paraffin-embedded (FFPE) cases diagnosed between 2002 and 2014 were retrieved from the pathology files of our institutions. Reverse transcription-polymerase chain reaction (RT-PCR) assays were optimized to detect WWTR1-CAMTA1 and YAP1-TFE3 fusion transcripts in FFPE tissue and transcription factor E3 (TFE3) protein accumulation was examined by immunohistochemistry (IHC). RNA was extracted from 33 adequate samples, with more recent cases providing a greater yield of high quality RNA. Fourteen of 18 informative cases were positive for WWTR1-CAMTA1 fusion transcripts, four of which showed higher-grade cytological features termed by some as 'malignant EHE'. Novel in-frame fusion transcripts were identified in four cases by direct sequencing. IHC revealed variable nuclear TFE3 staining in six of 17 cases; three with patchy staining showed WWTR1-CAMTA1 fusion. One of 18 informative cases was positive for YAP1-TFE3 fusion and showed strong nuclear TFE3 staining by IHC. Conclusions: This study confirms the high incidence of WWTR1-CAMTA1 and YAP1-TFE3 rearrangements in EHE and indicates that the staining pattern for TFE3 IHC is critical for specificity.
Original language | English (US) |
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Pages (from-to) | 699-708 |
Number of pages | 10 |
Journal | Histopathology |
Volume | 67 |
Issue number | 5 |
DOIs | |
State | Published - Nov 2015 |
Keywords
- CAMTA1
- Epithelioid
- Haemangioendothelioma
- Sarcoma
- TFE3
- Translocation
- WWTR1
- YAP1
ASJC Scopus subject areas
- Pathology and Forensic Medicine
- Histology