Clear cell sarcoma of the mediastinum

A 59-year-old woman presented with a large mediastinal mass. At thoracotomy, the mass was found tightly adherent to the esophageal wall and right lower lobe of the lung. Histological examination showed a solid tumor composed of closely packed nests of cells with clear and eosinophilic cytoplasm, which were strongly and diffusely positive for S 100 protein but negative for HMB45 and Melan-A. The diagnosis of clear cell sarcoma was supported by demonstrating the presence of an EWS gene rearrangement by fluorescence in situ hybridization. There was no evidence that this lesion represented metastatic disease. To the best of our knowledge, primary mediastinal clear cell sarcoma has not been previously reported in the literature. We present the case and discuss the differential diagnosis. (C) 2009 Elsevier Inc. All rights reserved

Detection of beta-catenin mutations in paraffin-embedded sporadic desmoid-type fibromatosis by mutation-specific restriction enzyme digestion (MSRED): An ancillary diagnostic tool

Desmoid-type fibromatosis is a locally aggressive deep soft tissue tumor. Some cases are associated with adenosis polyposis coli germline mutations whereas others harbor somatic P-catenin point mutations mainly in exon 3, codons 41 and 45. These mutations result in stabilization of P-catenin, and activation of the Writ signaling pathway. The aim of this study was to determine the specificity and sensitivity of these 3 most common P-catenin mutations in the diagnosis of desmoid-type fibromatosis using paraffin-embedded material. The results were compared with nuclear expression of P-catenin. Mutation-specific restriction enzyme digestion methodology was employed to detect the 3 mutations. One hundred and thirty-three cases were analyzed, including 76 desinoid-type, and 18 superficial fibromatosis, in addition to a further 39 fibromatosis mimics. A restriction site was present for analysis of the codon 41 mutation. Mismatch primers were designed for the codon 45 mutations. Mutations were detected in 66 cases (87%) of 76 desmoid-type fibromatosis (71 extra-abdominal). Of these, 34 (45%) were in codon 45 (TCT > TTT), 27 (35%) in codon 41 (ACC > GCC), and 5 (7%) in codon 45 (TCT > CCT). No mutations were detected in the other lesions studied. All desmoid-type fibromatosis cases and 72% of the mimics teste