目的:探讨成纤维细胞结缔组织痣（fibroblastic connective tissue nevus, FCTN）的临床病理学特征、免疫组织化学（免疫组化）表型及鉴别诊断。方法:1例2岁的女性患儿出现右大腿鲜红色硬化斑块,边界清晰,形状不规则。予患儿行活体组织检查（活检）手术,对病变组织进行苏木精-伊红（hematoxylin-eosin,HE）染色及免疫组化染色,观察肿瘤的组织学形态和免疫表型,分析其临床病理特征,并结合相关文献进行探讨,同时与其他类似的梭形细胞瘤相鉴别。结果:本例报道患者的病理组织在光学显微镜下观察,表现为梭形细胞浸润于真皮深部,可波及皮下脂肪,皮肤附件不受累,肿瘤细胞绕毛囊、汗腺生长,弹力纤维出现分裂并减少;免疫组化检查示,CD34阳性,平滑肌肌动蛋白（smooth muscle actin,SMA）呈局灶弱阳性,S100（-）,结蛋白（-）,Ki-67（1%+）。复习目前所有报道的45例FCTN病例,患者普遍发病年龄较早（中位数为10岁）,好发于儿童的躯干和头颈部,均表现为无痛斑状或结节。本例报道患者的临床表现、病理特点及免疫组化结果与既往报道相一致。结论:FCTN是一种罕见的错构瘤,为结缔组织痣的变异型,可向肌成纤维和成纤维细胞分化。本病需与恶性肿瘤如隆突性皮肤纤维肉瘤、先天性婴儿纤维肉瘤及横纹肌肉瘤等软组织肿瘤相鉴别。

Objective: To analyze the clinic-pathological features, immunohistochemical phenotype and differential diagnosis of a child with fibroblastic connective tissue nevus（FCTN）. Methods: A 2-year-old girl developed bright red sclerotic plaque on her right thigh with clear boundary and irregular shape. Biopsy was performed on the lesion, and the pathological tissues were stained with HE and immunohistochemistry. The immunohistochemical phenotypes for differential diagnosis were analyzed along with literature review. Results: Histologically, the lesion was composed of bundles of bland spindle cells of fibroblastic/myofibroblastic lineage irregularly branching within the reticular dermis and along fibrous septa in the subcutis, without affecting the adnexal structures. The dermal adipocytes were entrapped by tumor cells, and elastic fibers were fragmented and decreased. Immunohistochemically, cells of FCTN were positive for CD34, and weak positive for SMA（smooth muscle actin） locally, while negative for S100, des, and low index of Ki-67(1%). Among the 45 cases reported, it was found that the patients generally had an early onset age (median 10 years old), and FCTN occured mostly in children’s trunk, head and neck, with painless spots or nodules as primary presentations. The clinic-pathological features and immunohistochemical phenotype of the patient described hereby were consistent with cases previously reported. Conclusions: FCTN is a rare variant of nevus of connective tissue, which could differentiate into myofibroblast and mechanocyte cells. Immunohistochemically, CD34 is usually positive and SMA is weakly positive in spindle cells. The FCTN should be differentiated with soft tissue tumor, such as dermatofibrosarcoma protuberans,congenital infantile fibrosarcoma and rhabdomyosarcoma.