Martorell Miguel, Pérez-Vallés Ana, Gozalbo Francisco, Garcia-Garcia Jose Angel, Gutierrez Jair, Gaona John
Department of Pathology, Hospital General Universitario, Valencia, Spain.
Diagn Pathol. 2007 Jun 18;2:19. doi: 10.1186/1746-1596-2-19.
Extrapleural Solitary Fibrous tumors (SFTs) have been increasingly reported. The retroperitoneum, deep soft tissues of proximal extremities, abdominal cavity, trunk, head and neck are the most common extraserosal locations reported. Microscopically they show a wide range of morphological features, and so the differential diagnosis is extensive. Immunohistochemically, they commonly express CD34, vimentin, bcl-2 and CD99. Epithelial membrane antigen (EMA) and smooth muscle actin (SMA) may occasionally be expressed. Epithelioid morphology in extrapleural SFT has only very occasionally been described (five cases reported), some of them with biphasic pattern and others with malignant characteristics.
A SFT of the thigh with epithelioid areas in a 63 year old woman is reported. Microscopically the tumor showed areas hypo and hipercellular. At the periphery of the hipercellular areas there were nodules composed of epithelioid cells. Immunohistochemically both the spindle and epithelioid cells were positive for CD34, vimentin, bcl-2 and CD99. Epithelial, neural and muscular markers were negative. Molecular study was done and ruled out a synovial sarcoma.
Ten cases of SFT of the thigh have been reported but to our knowledge this is the first case with epithelioid morphology affecting the extremities. Identification of this pattern of SFT is of importance, to avoid misdiagnosis with other more aggressive conditions in soft tissue.
胸膜外孤立性纤维性肿瘤（SFTs）的报道日益增多。腹膜后、近端肢体深部软组织、腹腔、躯干、头颈部是报道中最常见的浆膜外部位。显微镜下，它们呈现出广泛的形态学特征，因此鉴别诊断范围广泛。免疫组化方面，它们通常表达CD34、波形蛋白、bcl-2和CD99。上皮膜抗原（EMA）和平滑肌肌动蛋白（SMA）可能偶尔表达。胸膜外SFT的上皮样形态仅偶尔被描述（报道了5例），其中一些具有双相模式，另一些具有恶性特征。
报告了一名63岁女性大腿部具有上皮样区域的SFT。显微镜下，肿瘤显示出细胞减少和增多的区域。在细胞增多区域的周边有由上皮样细胞组成的结节。免疫组化显示，梭形细胞和上皮样细胞CD34、波形蛋白、bcl-2和CD99均呈阳性。上皮、神经和肌肉标志物均为阴性。进行了分子研究，排除了滑膜肉瘤。
已报道10例大腿部SFT，但据我们所知，这是第一例影响肢体的具有上皮样形态的病例。识别这种SFT模式很重要，以避免与软组织中其他更具侵袭性的疾病误诊。
