结节性纤维毛囊瘤：一种新的皮肤附属器肿瘤

Nodular fibrofolliculoma：a new entity of skin adnexal tumor

患者女，22岁，左肩部孤立性无痛性肿物逐渐增大2年人院。体检：除左肩部肿块外其余各系统检查未见异常。皮肤科检查：病变局部皮肤隆起，表面光滑，色泽正常，肿物位于皮下，约3．5am×2．0cm×1．5cm，质硬，可移动。局麻下行肿块切除，术中见肿物位于皮下脂肪组织内，结节状，局部具有纤维性假包膜，肿物切面灰白色，质中。镜下，肿瘤组织学形态与乳腺型纤维腺瘤极为相似，呈明显的分叶状，每个小叶由具有管状结构、基底细胞样上皮条索和富于成纤维细胞样细胞的纤维黏液样间质构成，小叶内无毛球和原始毛乳头结构；小叶间为致密的胶原纤维性分隔，其间散在少量炎细胞浸润；多数小叶内基底细胞样上皮条索包绕在纤维黏液样间质周围；部分管状结构内可见少许稀薄并呈同心圆样排列的淡嗜伊红物质。免疫组化显示，小叶内上皮细胞及其管腔内物质强阳性表达细胞角蛋白5／6（CK5／6），不表达CAM5．2及癌胚抗原（CEA），管腔内淡嗜伊红物质糖原染色阴性，支持管状结构为不成熟毛囊，而非汗管。结合临床表现、形态学特点、免疫组化及糖原染色结果，命名为结节性纤维毛囊瘤（nodular fibrofolliculma）。术后随访3月余未见复发。本病是一种毛源性良性附属器肿瘤，具有独特的病理学表现，认为是一种新的皮肤附属器肿瘤。

A 22-year-old patient was admitted to the hospital with a solitary, gradually growing and painless mass in the left shoulder for 2 years. Physical examination revealed no abnormality except for the skin lesion. Skin examination showed an elevated lesion measuring about 3.5 cm×2.0 cm×1.5 cm with smooth surface and normal color, which was located in the subeutaeous tissue, indurated and movable. Resection of the tumor was performed under local anesthesia. On visual observation during operation, the tumor was sited in the subcutaneous fat tissue, nodular-like and surrounded locally by fibrous pseudocapsules with a grey incisal surface and mild texture. Microscopically, the tumor was extremely similar to breast fibroadenoma with muhiple lobuli, and each of the lobuli was composed of tubiform structures, basal cell-like epithelial cell trabs and fibromyxoid stroma abundant in fibroblast-like spindle cells. No hair bulb or primitive dermal papillae were observed in the lobnli, which were separated by compact collagen fibers infiltrated by a few scattered inflammatory cells. Fibromyxoid stroma was surrounded by basal cell-like epithelial cell strabs in most lobuli, and some tubiform structures were filled with a little thin lightly eosinophilic material in a concentric arrangement. Immunohistochemistry showed that intralobular epithelial cells were strongly positive for eytokeratin 5/6, but negative for CAM5.2 or carcinoembryonic antigen （CEA）. In addition, the lightly eosinophilic material in lumens was negative for periodic acid-Schiff （PAS） staining. These results suggested that the tubiform structures were immature follicles, but not sweat ducts. The patient was diagnosed with nodular fibrofolliculoma （NFF） based on the clinical manifestations, morphological features, immunohistoehemieal and PAS staining results. No relapse was observed in more than 3 months of postoperative follow-up. As a benign triehogenic adnexal neoplasm with unique clinieopathologieal manifestations, NFF may be a new entity of cutaneous adnexal neoplasm.