CTNNB1突变在软组织肿瘤的发生发展中起重要作用,如纤维瘤样纤维瘤病（DF），鼻窦血管纤维瘤,鼻窦血管外皮细胞瘤,结内栅栏状肌纤维母细胞瘤，神经肌肉性脉络膜瘤（NMC），和最近报道的假内分泌肉瘤。这里,我们报道了一种独特的混合性软组织肿瘤与经典的DF，不寻常的上皮样成分，NMC是一名23岁的女性。经典的DF和NMC以及不寻常的上皮样成分和NMC局部混合并且彼此密切相关。免疫组织化学，DF,不寻常的上皮样成分，NMC对β-连环蛋白表现出不同程度的核阳性。更关键的是,上述所有成分均具有相同的CTNNB1p.Ser45Pro错义突变。据我们所知,这是唯一报道的CTNNB1突变驱动的与DF的杂种肿瘤，不寻常的上皮样成分，NMC。本病例进一步证实，CTNNB1突变的软组织肿瘤具有高度异质性，但是形态谱是宽而连续的。
CTNNB1 mutations play important roles in the development of soft tissue tumors, such as desmoid fibromatosis (DF), sinonasal tract angiofibroma, sinonasal glomangiopericytoma, intranodal palisaded myofibroblastoma, neuromuscular choristoma (NMC), and the recently reported pseudoendocrine sarcoma. Here, we report a unique hybrid soft tissue tumor with classic DF, unusual epithelioid component, and NMC in a 23-year-old female. The classic DF and NMC and the unusual epithelioid component and NMC were locally intermixed and closely related to each other. Immunohistochemically, the DF, unusual epithelioid component, and NMC exhibited nuclear positivity for β-catenin to varying degrees. More critically, all of the above components harbored identical CTNNB1 p.Ser45Pro missense mutations. To the best of our knowledge, this is the only reported CTNNB1 mutation-driven hybrid tumor with DF, unusual epithelioid component, and NMC. The present case further confirmed that CTNNB1-mutational soft tissue tumors are highly heterogeneous, but the morphological spectrum is wide and consecutive.
