黏液样隆突性皮纤维肉瘤的临床病理学观察

Myxoid dermatofibrosarcoma protuberans： a clinicopathologic analysis of 16 cases

目的探讨黏液样隆突性皮纤维肉瘤（DFSP）的临床病理学特征及其鉴别诊断。方法回顾性复习16例黏液样DFSP的临床资料、组织学形态和免疫学表型。结果患者中男15例，女1例，平均和中位年龄分别为47和48岁，年龄范围为11～73岁。11例位于躯干，2例位于肩部，2例位于头皮，1例位于上臂。临床表现与经典型DFSP相似，表现为皮下缓慢性生长的结节，部分病例近期生长迅速。16例中的12例为原发性，4例为复发性。肿瘤直径为2．0～10．0cm（平均5．0cm）。镜下观察：肿瘤境界不清，呈浸润性生长，其中7例完全呈黏液样，由短梭形和星状细胞、大量的黏液样基质和纤细的血管网组成，核分裂象范围为（0～10）／HPF；另9例除黏液样区域外，5例可见经典型DFSP区域，其中1例含有灶性的巨细胞纤维母细胞瘤样区域，另4例则呈纤维肉瘤样变。免疫组织化学标记显示，所有病例均表达CD34，但与经典型DFSP相比，阳性强度相对较弱。随访显示，4例复发性病例中l例发生肺转移和局部复发。结论黏液样DFSP是DFSP的一种少见亚型，当肿瘤完全呈黏液样时容易被误诊为其他类型的黏液样软组织肿瘤，在诊断时应注意加以鉴别。

Objective To study the clinicopathologic features and differential diagnosis of myxoid dermafibrosarcoma protuberans （DFSP）. Methods The clinical and pathologic features of 16 cases of myxoid DFSP were reviewed. Results There were altogether 15 males and 1 female. The age of the patients ranged from 11 to 73 years （mean = 47 years and median = 48 years）. The commonest site of involvement was trunk （number = 11 ）, followed by shoulder （number = 2） , head and neck （number = 2）, and extremity （number = 1 ）. Similar to conventional DFSP, most patients presented with a slowly enlarging subcutaneous nodule which showed a rapid recent growth in some cases. Amongst the 16 cases studied, 12 occurred de novo and 4 represented local recurrence. The tumors ranged from 2 to 10 cm in greatest dimension （mean = 5 cm and median = 4 cm）. Histologcically, they were poorly circumscribed and located in the dermis, with focal infiltration into the underlying subcutaneous tissue. Seven cases were purely myxoid and composed of spindly and stellate cells with delicate arborizing vascular meshwork. The remaining 9 cases were predominantly myxoid （ 〉 50% ）, with 5 cases containing cellular areas resembling conventional DFSP and 4 cases showing fibrosarcomatous transformation. In addition, foci of giant cell fibroblastoma-like areas were noted in 1 case. Immunohistochemical study showed that the tumors cells were positive for CD34. The staining was weak in the myxoid areas, as compared with conventional DFSP. Of the 4 recurrent cases, one patient developed lung metastases. Conclusions Myxoid DFSP represents a rare variant of DFSP and may pose important diagnostic pitfalls. It is especially so if the tumor purely consists of myxoid element. Familiarity with the histologic features helps to avoid misdiagnosis.