Vanni R, Faa G, Dettori T, Melis G B, Dumanski J P, O'Brien K P
Department of Applied Sciences Biosystems, University of Cagliari, Cittadella Universitaria, Italy.
Virchows Arch. 2000 Jul;437(1):95-100. doi: 10.1007/s004280000184.
Dermatofibrosarcoma protuberans (DFSP) is a highly recurrent low-grade soft tissue sarcoma, which is usually located on the trunk. Presentation in the vulva is rare, with only 13 cases being reported to date, none of which have been investigated at the cytogenetic or molecular level. Specific cytogenetic abnormalities, involving chromosomes 17 and 22, are characteristic features of DFSP and giant cell fibroblastoma (GCF), a tumor closely related to DFSP. These chromosomal rearrangements result in the fusion of the COL1A1 and PDGFB genes in both lesions and show wide variation in the position of the fusion point in COL1A1. Here, we describe a case of DFSP of the vulva with a typical monotonous storiform pattern, with no foci of multinucleated giant cells. Cytogenetic analysis showed a 47,XX,+r karyotype in 50% of the cells, and molecular investigation disclosed the presence of a transcript fusing COL1A1 exon 37 to PDGFB exon 2. This is the first case of DFSP showing such a fusion point, which is intriguingly identical to that found in a GCF case, indicating that the COL1A1/PDGFB fusion point position does not seem to affect tumor morphology. This finding further underlines the very close relationship between these two morphologically distinct entities.
隆突性皮肤纤维肉瘤（DFSP）是一种极易复发的低级别软组织肉瘤，通常位于躯干。在外阴出现的情况罕见，迄今为止仅报告过13例，其中无一例进行过细胞遗传学或分子水平的研究。涉及17号和22号染色体的特定细胞遗传学异常是DFSP和巨细胞纤维母细胞瘤（GCF，一种与DFSP密切相关的肿瘤）的特征性表现。这些染色体重排导致这两种病变中COL1A1和PDGFB基因融合，且COL1A1融合点位置存在广泛变异。在此，我们描述一例具有典型单调席纹状模式的外阴DFSP病例，无多核巨细胞灶。细胞遗传学分析显示50%的细胞具有47,XX,+r核型，分子研究发现存在一种将COL1A1外显子37与PDGFB外显子2融合的转录本。这是首例显示这种融合点的DFSP病例，有趣的是该融合点与在一例GCF病例中发现的完全相同，表明COL1A1/PDGFB融合点位置似乎不影响肿瘤形态。这一发现进一步强调了这两种形态学上不同的实体之间的密切关系。
