Case report
Small blue round cell tumor of the interosseous membrane bearing a t(2;22)(q34;q12)/EWS-CREB1 translocation: a case report
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* Corresponding author: Torsten O Nielsen torsten@interchange.ubc.ca
1 Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, Canada
2 Department of Pathology, British Columbia Cancer Agency, Vancouver, Canada
3 Division of Surgical Oncology, British Columbia Cancer Agency, Vancouver, Canada
Molecular Cytogenetics 2010, 3:12 doi:10.1186/1755-8166-3-12
Published: 2 July 2010Abstract
Background
The group of small blue round cell tumors encompasses a heterogeneous group of neoplasms characterized by primitive appearing round cells with few distinguishing histologic features.
Results
We report the case of a small blue round cell tumor with an EWS gene rearrangement detected by fluorescent in situ hybridization (FISH) analysis that mimicked Ewing sarcoma, but with unusual histology and immunohistochemical features. Multi-color karyotyping identified the presence of a t(2;22)(q34;q12) that was initially expected to represent a variant EWSR1-FEV translocation. After an extensive workup, the lesion is considered to represent a clear cell sarcoma harboring an EWSR1-CREB1 fusion transcript.
Conclusions
This case appears to represent a rare variant of clear cell sarcoma arising in peripheral soft tissues with unusual histology and unique immunophenotype. In this circumstance, FISH for all EWSR1 translocation partners or RT- PCR for a spectrum of possible transcript variants is critically important for diagnosis, since cytogenetic analysis or clinical FISH assay using only commercial EWSR1 probes will be misleading.