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<p>Abstract</p> <p>Background</p> <p>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.</p> <p>Results</p> <p>We report the case of a small blue round cell tumor with an <it>EWS </it>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 <it>EWSR1-FEV </it>translocation. After an extensive workup, the lesion is considered to represent a clear cell sarcoma harboring an <it>EWSR1-CREB1 </it>fusion transcript.</p> <p>Conclusions</p> <p>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 <it>EWSR1 </it>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 <it>EWSR1 </it>probes will be misleading.</p>