Rao Priya, Colen Rivka R, Bruner Janet M, Meis Jeanne M
Departments of Pathology and Houston, TX, USA.
Departments of Radiology, University of Texas MD Anderson Cancer Center , Houston, TX, USA.
Rare Tumors. 2014 Dec 18;6(4):5586. doi: 10.4081/rt.2014.5586. eCollection 2014 Oct 27.
Extraskeletal myxoid chondrosarcoma is a rare soft tissue neoplasm that occurs predominantly in the soft tissues of the lower extremities. Herein we present a case of a 29 year old male who presented with bilateral femoral numbness believed to be the result of prior injury to his back. A magnetic resonance imaging revealed a mass in the T4-T5 epidural space compressing the spinal cord. Laminectomy was performed and the lesion removed piecemeal. The pathology specimen consisted of multiple fragments of dura involved by a myxoid neoplasm with a nodular growth pattern. The tumor cells were arranged in anastomosing cords and strands. Individual tumor cells were small, of uniform size and shape, with small hyperchromatic nuclei and scant eosinophilic cytoplasm. Immunohistochemical stains were performed which showed the tumor cells were diffusely positive for vimentin and focally positive for EMA, S-100 protein and cytokeratin, whereas they were negative for CD34 and CD99. Fluorescence in situ hybridization (FISH) studies showed a clonal population of cells with re-arrangement of the EWSR1 locus, confirming the histologic impression of extraskeletal myxoid chondrosarcoma. This is the first report of a case of an extraskeletal myxoid chondrosarcoma arising from the dura, confirmed to have rearrangement of the EWSR1 gene by FISH. There have only been two other cases of dural based extraskeletal myxoid chondrosarcoma reported prior to our case. We also briefly review the published literature and discuss differential diagnostic considerations for this rare tumor.
骨外黏液样软骨肉瘤是一种罕见的软组织肿瘤，主要发生在下肢软组织。在此，我们报告一例29岁男性病例，该患者因双侧股骨麻木就诊，据信这是其既往背部受伤的结果。磁共振成像显示T4 - T5硬膜外间隙有一肿块压迫脊髓。行椎板切除术并将病变组织分块切除。病理标本由多个被黏液样肿瘤累及的硬脑膜碎片组成，肿瘤呈结节状生长模式。肿瘤细胞排列成交错的条索状。单个肿瘤细胞较小，大小和形状均匀，核小、深染，嗜酸性胞质稀少。进行了免疫组化染色，结果显示肿瘤细胞波形蛋白弥漫阳性，上皮膜抗原（EMA）、S - 100蛋白和细胞角蛋白局灶阳性，而CD34和CD99阴性。荧光原位杂交（FISH）研究显示一群具有EWSR1基因座重排的克隆细胞，证实了骨外黏液样软骨肉瘤的组织学印象。这是首例源自硬脑膜的骨外黏液样软骨肉瘤病例报告，经FISH证实有EWSR1基因重排。在我们的病例之前，仅另有两例基于硬脑膜的骨外黏液样软骨肉瘤病例报告。我们还简要回顾了已发表的文献，并讨论了这种罕见肿瘤的鉴别诊断要点。
