Abstract：
Dermatofibroma (DF) is a benign tumor that forms pedunculated lesions ranging in size from a few millimeters to 2 cm, usually affecting the extremities and trunks of young adults. Histopathologically, DF is characterized by the storiform proliferation of monomorphic fibroblast-like spindle cells. In addition to neoplastic cells, secondary elements such as foamy histiocytes, Touton-type giant cells, lymphoplasmacytes, and epidermal hyperplasia are characteristic histological features. Several histological variants, including atypical, cellular, aneurysmal, and lipidized variants, have been reported; cases with variant histologies are sometimes misdiagnosed as sarcomas. We present a case of metastasizing aneurysmal DF that was initially diagnosed as an angiosarcoma on biopsy. A 26-year-old woman was referred to our hospital with a gradually enlarging subcutaneous mass in her lower left leg. Positron emission tomography-computed tomography revealed high fluorodeoxyglucose uptake not only in the tumor but also in the left inguinal region. On biopsy, ERG and CD31-positive atypical spindle cells proliferated in slit-like spaces with extravasation, leading to the diagnosis of angiosarcoma. Histology of the wide-resection specimen was consistent with DF, and lymph node metastasis was also observed. Nanopore DNA sequencing detected CD63::PRKCD fusion and copy number gain, although CD63 was not included in the target region of adaptive sampling. This report highlights the importance of recognizing the unusual clinical, radiological, and pathological features of DF to avoid misdiagnosis, and the potential diagnostic utility of nanopore sequencer.
摘要：
皮肤纤维瘤（DF）是一种良性肿瘤，形成大小从几毫米到2厘米不等的带蒂病变，通常影响年轻人的四肢和躯干。组织病理学,DF的特征是单形成纤维细胞样梭形细胞的晶体样增殖。除了肿瘤细胞,次级元素，如泡沫组织细胞，Touton型巨细胞,淋巴浆细胞,表皮增生是特征性的组织学特征。几种组织学变异，包括非典型的，细胞，动脉瘤，和液化的变体，有报道；组织学变异的病例有时被误诊为肉瘤。我们介绍了一例转移性动脉瘤性DF，最初在活检中被诊断为血管肉瘤。一名26岁的妇女因左小腿皮下肿块逐渐扩大而被转诊到我们医院。正电子发射断层扫描-计算机断层扫描显示，不仅在肿瘤中而且在左腹股沟区域都有高的氟脱氧葡萄糖摄取。活检时，ERG和CD31阳性非典型梭形细胞在狭缝样间隙中增殖并外渗，导致血管肉瘤的诊断。宽切除标本的组织学与DF一致，淋巴结转移。纳米孔DNA测序检测到CD63::PRKCD融合和拷贝数增加，尽管自适应采样的目标区域不包括CD63.本报告强调了认识到不寻常的临床，放射学,和DF的病理特征，以避免误诊，和纳米孔测序仪的潜在诊断效用。
