Abstract：
Diagnosis of desmoid-type fibromatosis (DF) may be challenging on biopsy due to morphologic overlap with reactive fibrosis (scar) and other uniform spindle cell neoplasms. Evaluation of nuclear β-catenin, a surrogate of Wnt pathway activation, is often difficult in DF due to weak nuclear expression and high background membranous/cytoplasmic staining. Lymphoid enhancer-factor 1 (LEF1) is a recently characterized effector partner of β-catenin which activates the transcription of target genes. We investigated the performance of LEF1 and β-catenin immunohistochemistry in a retrospective series of 156 soft tissue tumors, including 35 DF, 3 superficial fibromatosis, and 121 histologic mimics (19 soft tissue perineurioma, 8 colorectal perineurioma, 4 intraneural perineurioma, 26 scars, 23 nodular fasciitis, 6 low-grade fibromyxoid sarcomas, 6 angioleiomyomas, 5 neurofibromas, 5 dermatofibrosarcoma protuberans, 3 low-grade myofibroblastic sarcomas, 3 synovial sarcomas, 3 inflammatory myofibroblastic tumors, 2 schwannomas, and 1 each of Gardner-associated fibroma, radiation-associated spindle cell sarcoma, sclerotic fibroma, dermatofibroma, and glomus tumor). LEF1 expression was not only seen in 33/35 (94%) of DF but also observed in 19/23 (82%) nodular fasciitis, 7/19 (37%) soft tissue perineurioma, 2/3 (66%) synovial sarcoma, and 6/26 (23%) scar, as well as in 1 radiation-associated spindle cell sarcoma. The sensitivity and specificity of LEF1 IHC for diagnosis of DF were 94% and 70%, respectively. By comparison, β-catenin offered similar sensitivity, 94%, but 88% specificity. Positivity for LEF1 and β-catenin in combination showed sensitivity of 89%, lower than the sensitivity of β-catenin alone (94%); however, the combination of both LEF1 and β-catenin improved specificity (96%) compared to the specificity of β-catenin alone (88%). Although LEF1 has imperfect specificity in isolation, this stain has diagnostic utility when used in combination with β-catenin.
摘要：
由于与反应性纤维化（疤痕）和其他均匀的梭形细胞肿瘤的形态学重叠，因此在活检中诊断纤维瘤病（DF）可能具有挑战性。核β-连环蛋白的评估，Wnt通路激活的替代物，由于弱的核表达和高的背景膜/细胞质染色,在DF中通常是困难的。淋巴增强因子1（LEF1）是最近表征的β-连环蛋白的效应子伴侣，可激活靶基因的转录。我们调查了LEF1和β-catenin免疫组织化学在156个软组织肿瘤的回顾性系列中的表现，包括35DF，3浅表纤维瘤病，和121个组织学模拟物(19个软组织神经鞘瘤，8结直肠神经鞘瘤，4神经内神经鞘瘤，26个伤疤,23个结节性筋膜炎,6低度纤维黏液样肉瘤，6血管平滑肌瘤，5神经纤维瘤，5隆突性皮肤纤维肉瘤，3低度肌纤维母细胞肉瘤，3滑膜肉瘤，3炎性肌纤维母细胞瘤，2个神经鞘瘤,加德纳相关的纤维瘤各1个，辐射相关梭形细胞肉瘤,硬化性纤维瘤,皮肤纤维瘤,和血管球瘤）。LEF1的表达不仅见于DF的33/35（94%），而且见于19/23（82%）结节性筋膜炎，7/19（37%）软组织神经鞘瘤，2/3（66%）滑膜肉瘤，和6/26（23％）疤痕，以及1个辐射相关的梭形细胞肉瘤。LEF1免疫组化诊断DF的敏感性和特异性分别为94%和70%,分别。相比之下,β-连环蛋白提供了类似的灵敏度，94%,但88%的特异性。LEF1和β-catenin联合阳性显示89%的敏感性，低于单独使用β-连环蛋白的敏感性(94%)；然而，与单独使用β-catenin的特异性(88%)相比,LEF1和β-catenin的组合提高了特异性(96%)。尽管LEF1在分离时具有不完美的特异性，当与β-连环蛋白组合使用时,该染色剂具有诊断效用。
