Rao UN, Surti U, Hoffner L, Howard T, Leger W, Contis L, Yaw K
Department of Pathology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, USA
Mol Diagn. 1996 Jun;1(2):99-107. doi: 10.1054/MODI00100099.
Background: Myxoid chondrosarcoma (MCS) is a rare, low-grade, indolent tumor that can occur in soft tissue and bone. It is, however, capable of distant metastases. Previous cytogenetic data include a translocation, t(9;22)(q22-31;q12), occurring in 6 of 14 cases of the extraskeletal variant of the disease. Recently, rearrangement of the EWS gene has been reported in MCS. Methods and Results: Three cases of MCS, two skeletal and one extraskeletal, were examined to identify primary cytogenetic changes and correlate these with immunohistochemical, ultrastructural, and flow-cytometric analysis. The extraskeletal variant of MCS revealed a clonal translocation, t(9;22)(q22;q12), and trisomy for chromosomes 5, 7, 8, 12, 18, and 19. Our two cases of skeletal MCS showed complex karyotypes. In one skeletal tumor, a cryptic translocation involving chromosome 6p21.3 was identified by fluorescence in situ hybridization analysis, using chromosome-specific libraries. Conclusions: Thus far, 50% of cases of extraskeletal MCS, including our cases, have demonstrated a specific translocation, t(9;22)(q22-31;q12). Identifying this translocation is useful in confirming the diagnosis of MCS. Additional cytogenetic and molecular analysis is useful for detecting this translocation, and is also essential to determine other regions of possible diagnostic importance, such as the 6p21.3 breakpoint demonstrated in the present study. These techniques may be most useful for the skeletal lesions, in light of their heterogeneous cell populations and karyotypic variability.
黏液样软骨肉瘤（MCS）是一种罕见的、低级别、生长缓慢的肿瘤，可发生于软组织和骨骼。然而，它能够发生远处转移。先前的细胞遗传学数据包括一种易位，即t(9;22)(q22 - 31;q12)，在14例该疾病的骨外变体病例中有6例出现。最近，EWS基因重排在MCS中已有报道。
对3例MCS病例进行了检查，其中2例为骨内型，1例为骨外型，以确定原发性细胞遗传学改变，并将其与免疫组织化学、超微结构和流式细胞术分析相关联。MCS的骨外变体显示出一种克隆性易位，即t(9;22)(q22;q12)，以及5、7、8、12、18和19号染色体三体。我们的2例骨内型MCS显示出复杂的核型。在1例骨内肿瘤中，使用染色体特异性文库通过荧光原位杂交分析鉴定出涉及6号染色体p21.3的隐匿性易位。
迄今为止，包括我们的病例在内，50%的骨外MCS病例已显示出一种特定的易位，即t(9;22)(q22 - 31;q12)。识别这种易位有助于确诊MCS。额外的细胞遗传学和分子分析有助于检测这种易位，对于确定其他可能具有诊断重要性的区域（如本研究中显示的6p21.3断点）也至关重要。鉴于骨骼病变细胞群体的异质性和核型变异性，这些技术可能对骨骼病变最为有用。
