Laboratory of Solid Tumors Genetics, Institute for Research on Cancer and Aging of Nice (IRCAN), CNRS UMR 7284/INSERM U1081, Université Côte d'Azur (UCA), Centre Hospitalier Universitaire de Nice, Faculté de Médecine, Nice, France.
Central Laboratory of Pathology, Nice University Hospital, Hôpital Pasteur, Nice, France.
Genes Chromosomes Cancer. 2019 Sep;58(9):673-679. doi: 10.1002/gcc.22754. Epub 2019 Apr 13.
Adipocytic tumors are rare in children and are mostly benign. Less than 25 cases of pediatric well-differentiated liposarcoma (WDLPS), atypical lipomatous tumors (ALT), and dedifferentiated liposarcoma (DDLPS) have been reported. Among them, only three cases were genetically analyzed. We describe the genetic features of a rapidly growing adipose tumor that occurred in the thigh of a 7-year-old girl. Histologically, it was composed of mature adipocytic cells with a few atypia. Molecular analysis showed high-level amplification of the 12q13-21 region including MDM2 among 64 amplified genes. MDM2 amplification is a diagnostic hallmark of ALT/WDLPS/DDLPS. In adult cases, it is typically located in ring or giant marker chromosomes. In the present case, extra-copies of MDM2 were located on double minute chromosomes (dmin). This raised the hypothesis of dmin being precursors of adult's rings and giant markers and may provide indications for a better understanding of the mechanisms of adipose tumor oncogenesis.
脂肪性肿瘤在儿童中较为罕见，且大多为良性。仅有 25 例儿童分化良好型脂肪肉瘤（WDLPS）、非典型性脂肪肉瘤（ALT）和去分化脂肪肉瘤（DDLPS）的报道，其中仅有 3 例进行了基因分析。我们描述了一例发生于 7 岁女孩大腿的快速生长的脂肪性肿瘤的遗传学特征。组织学上，它由成熟的脂肪细胞组成，伴有少量异型性。分子分析显示在 64 个扩增基因中包括 12q13-21 区域的 MDM2 高水平扩增。MDM2 扩增是 ALT/WDLPS/DDLPS 的诊断标志。在成人病例中，它通常位于环状或巨大标记染色体上。在本病例中，MDM2 的额外拷贝位于双微小染色体（dmin）上。这提出了 dmin 是成人环和巨大标记物的前体的假说，可能为更好地理解脂肪性肿瘤发生机制提供线索。
