树突状纤维黏液样脂肪瘤的临床病理学分析

Clinicopathologic analysis of dendritic fibromyxolipoma

目的：探讨树突状纤维黏液样脂肪瘤（dendritic fibromyxolipoma,DFML）的临床病理学特征,并探讨容易与其混淆的软组织肿瘤的鉴别诊断。方法：收集5例树突状纤维黏液样脂肪瘤患者的临床资料,观察并分析其临床特征、组织病理学特征及免疫表型,并复习相关文献。结果：患者均为中老年男性,年龄45~80岁,平均59岁,肿瘤位于颈部、背部或肩胛部的浅表皮下或肌筋膜内。临床表现主要为局部肿块及其压迫症状。肿瘤直径3~8 cm,与周围组织界限清楚。大体观察为圆形或类圆形肿物,有完整包膜,切面灰黄色,部分呈黏液样或胶冻样。显微镜下肿瘤内增生的小梭形或星状细胞弥漫分布,成熟脂肪细胞掺杂其中,无不成熟的脂肪母细胞,间质多呈黏液样。高倍镜下,瘤细胞的胞质呈细长分支状突起,无细胞异型性及病理性核分裂象。此外,该肿瘤也含有较丰富的丛状小血管和毛细血管。免疫组织化学染色标记瘤细胞显示：5例肿瘤的Vimentin、CD34和BCL-2均呈阳性,S-100、CK均呈阴性,Ki-67阳性率小于2%或为阴性。结论：树突状纤维黏液样脂肪瘤是一种好发于中老年男性的特殊亚型脂肪瘤,其生物学行为属于良性,与梭形细胞脂肪瘤等多种软组织肿瘤的病理学特征极为相似,免疫组织化学染色有助于诊断与鉴别诊断。

Objective： To investigate the clinicopathologic characteristics of dendritic fibromyxolipoma for the purpose of differentiating it from other confusable soft tissue neoplasms. Methods： The clinicopathologic features in 5 cases of DFML were collected. Their clinicopathological histologic characteristics and immunophenotypes were analyzed. Results： The patients were middle-aged to elderly men, which between 45 and 80 years of age. The tumors were located in the subcutaneous tissues or muscular fascia of the neck region, back and shoulder. The main clinical manifestations were local mass and pressure symptom. The diameter of DFMLs was between 3 and 8 cm and clear edge in DFMLs. Grossl）5 it is circular or nearly-circular, partly thinly encapsulated lesion with focal mucinous or gelatinous cutting which presented yellowish. Histologicallyj the tumor was characterized by an admixture of mature adipocytes, spindle and stellate cells and abundant myxoid stroma. At high magnification, the tumor ceils showed thin cytoplasmic dentritic prolongations, and no cytological atypia or mitotic activity could be identified.Furthermore, the lesions were rich in plexiform small blood vessels and capillaries. Immunohistochemical results showed that tumor cells were positive for vimentin, CD34 and BCL-2, negative for S-100 and CK, less than 2% positive rate or negative for Ki67. Conclusion. Dendritic fibromyxolipoma is a special variant of lipoma with a predilection for middle to old aged males, whose pathological features were closely similar to other soft tissue tumors, such as spindle cell lipoma. Its biological behavior is benign, and immunohistochemical staining is helpful to the diagnosis and differential diagnosis.