上皮样纤维组织细胞瘤临床表现为红棕色结节状或息肉样病变；好发于中青年四肢（下肢多见），预后好，少数切除不干净而复发；
病变位于真皮内，肿瘤境界清楚，呈半圆形或息肉样；瘤细胞常呈镶嵌状排列，细胞核空泡状，可见小嗜酸性核仁，胞质丰富，嗜酸性；部分病例间质可伴明显胶原化；少数病例可呈神经束膜瘤样漩涡状生长方式；少数病例瘤细胞可见双核、三核、多核，或可见核沟、核内假包涵体；少数病例胞质透明，类似于PEComa；也有“软骨母细胞瘤样”上皮样纤维组织细胞瘤的报道，形态学如下图：
图1“软骨母细胞瘤样”上皮样纤维组织细胞瘤：患者，女，16岁，表现为结节样病变（A）；
可见典型上皮样纤维组织细胞瘤的区域及钙化（B）；局灶呈软骨母细胞瘤样的钙化形态（C）；瘤细胞弥漫表达ALK（D）；
图2“软骨母细胞瘤样”上皮样纤维组织细胞瘤：患者，女性，19岁，镜下见多灶状钙化区（A和B）；可见典型上皮样纤维组织细胞瘤区域（C）和反应性破骨细胞样巨细胞（D）；瘤细胞弥漫表达ALK（E）；
DISCUSSION
To the best of our knowledge, epithelioid fibrous histiocytomasshowing “chondroblastoma-like” calcification have not been previouslyreported, and it is likely that similar cases have historically beendiagnosed as representing other entities. Indeed, we were able toconfidently recognize these very unusual calcifying dermal tumors asvariants of epithelioid fibrous histiocytoma only with the assistanceof ALK immunohistochemistry, an ancillary test which we would not
have thought to use in the past. Similarly, application of ALK immunohistochemistryhas recently allowed for the recognition of “perineurioma-like” epithelioid fibrous histiocytomas. Calcification alsoappears to be an exceedingly rare phenomenon in fibrous histiocytomamore generally.
The differential for “chondroblastoma-like” epithelioid fibroushistiocytomas includes a variety of dermal and subcutaneous epithelioidlesions that can show calcifications and/or chondro-osseousmatrix. These include epithelioid sarcoma, cutaneous syncytial myoepithelioma,“chondroblastoma-like” soft tissue chondromas malignantmelanoma with osteo/chondrosarcomatous differentiation, extraskeletalosteosarcoma and ossifying fibromyxoid tumor of soft parts.
上皮样纤维组织细胞瘤
免疫组化
瘤细胞ALK阳性（根据伙伴基因不同，阳性部位也不同）；部分病例表达TFE3；60%病例至少出现局灶EMA阳性；不表达S100；
细胞遗传学
ALK伙伴基因有SQSTM1（最常见）、VCL、DCTN1、ETV6、PPFIBP1、SPECC1L、TMP3、PRKAR2A、MLPH和EML4；未见TFE3基因基因断裂的报道；
鉴别诊断
①Spitz痣；②spitzoid黑色素瘤；③化脓性肉芽肿；④皮肤肌上皮瘤；
参考文献
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