Mentzel Thomas, Schärer Leo, Kazakov Dmitry V, Michal Michal
Dermatopathologische Gemeinschaftspraxis, Friedrichshafen, Germany.
Am J Dermatopathol. 2007 Oct;29(5):443-8. doi: 10.1097/DAD.0b013e318145413c.
Dermatofibrosarcoma protuberans (DFSP) represents a locally aggressive mesenchymal neoplasm of skin and subcutis with characteristic clinicopathologic, immunohistochemical, and molecular findings. In addition to typical cases, morphologic variants such as pigmented, fibrosarcomatous, myofibroblastic, and granular cell DFSP have been described. Purely or predominantly myxoid DFSP is extremely rare, and may cause considerable diagnostic problems. Eight cases of predominantly myxoid DFSP were studied. Paraffin-embedded blocks and slides were retrieved from the files of the authors. Clinical data were obtained from the referring pathologists and dermatologists. Immunohistochemistry was performed using the ABC method, and three cases were studied by polymerase chain reaction technique. There were six male and two female patients (age range: 29 to 74 years). Locations included the inguinal area (three cases), thigh, upper arm, shoulder, abdominal wall, and back (one each). The patients were treated by wide excision as well as reexcision. Tumor size ranged from 1.5 to 12 cm. Histologically, a nodular growth with peripheral diffuse infiltration, as well as a diffusely infiltrating growth of relatively uniform spindled and stellated tumor cells containing slightly enlarged nuclei, was noted. Three cases were entirely myxoid, and in five cases more than 80% of the tumor area showed myxoid stromal changes. In two cases each, focal fibrosarcomatous and focal giant cell fibroblastoma-like changes were present. At least focally, hypocellular areas were evident in one case. Scattered enlarged tumor cells were seen in two cases. The mitotic rate ranged from 1 to 10 mitoses in 10 high-power fields. Numerous blood vessels with slightly fibrosed vessel walls were seen in seven cases. Immunohistochemically, tumor cells in all cases stained positively for CD34, and in one case each a focal expression of alpha-smooth muscle actin and epithelial membrane antigen (EMA) was noted. The remaining antibodies (CD99, CD31, S-100, Factor XIIIa) were all negative. Polymerase chain reaction technique showed in one case the characteristic COL1A1-PDGFB fusion gene. Follow-up information in seven cases (range: 2 months to 10 years; mean: 62 months; median: 48 months) revealed a local recurrence at 5 years. In conclusion, myxoid DFSP represents a very rare morphologic variant with characteristic changes that has to be distinguished from benign and malignant myxoid mesenchymal neoplasms as superficial angiomyxoma, superficial acral fibromyxoma, myxoid solitary fibrous tumor, myxoid perineurioma, low-grade myxofibrosarcoma, low-grade fibromyxoid sarcoma, myxoid liposarcoma, and myxoid synovial sarcoma.
隆突性皮肤纤维肉瘤（DFSP）是一种发生于皮肤和皮下组织的具有局部侵袭性的间叶性肿瘤，具有特征性的临床病理、免疫组化及分子学表现。除典型病例外，还描述了色素性、纤维肉瘤样、肌纤维母细胞性及颗粒细胞性DFSP等形态学变异型。纯黏液样或主要为黏液样的DFSP极为罕见，可能会导致相当大的诊断难题。对8例主要为黏液样的DFSP进行了研究。从作者的档案中检索出石蜡包埋块和切片。临床资料来自转诊的病理学家和皮肤科医生。采用ABC法进行免疫组化，3例采用聚合酶链反应技术进行研究。患者中男性6例，女性2例（年龄范围：29至74岁）。病变部位包括腹股沟区（3例）、大腿、上臂、肩部、腹壁及背部（各1例）。患者接受了广泛切除及再次切除治疗。肿瘤大小为1.5至12 cm。组织学上，可见结节状生长伴周边弥漫性浸润，以及相对一致的梭形和星状肿瘤细胞呈弥漫性浸润生长，细胞核略增大。3例完全为黏液样，5例超过80%的肿瘤区域呈现黏液样间质改变。各有2例出现局灶性纤维肉瘤样及局灶性巨细胞纤维母细胞瘤样改变。1例至少在局部可见细胞稀少区。2例可见散在的增大肿瘤细胞。有丝分裂率为每10个高倍视野1至10个有丝分裂象。7例可见大量血管，血管壁轻度纤维化。免疫组化方面，所有病例的肿瘤细胞CD34染色均为阳性，各有1例出现α-平滑肌肌动蛋白和上皮膜抗原（EMA）的局灶性表达。其余抗体（CD99、CD31、S-100、因子ⅩⅢa）均为阴性。聚合酶链反应技术在1例中显示出特征性的COL1A1-PDGFB融合基因。7例患者的随访信息（范围：2个月至10年；平均：62个月；中位数：48个月）显示5年时出现局部复发。总之，黏液样DFSP是一种非常罕见的形态学变异型，具有特征性改变，必须与良性和恶性黏液样间叶性肿瘤如浅表血管黏液瘤、浅表肢端纤维黏液瘤、黏液样孤立性纤维性肿瘤、黏液样神经束膜瘤、低级别黏液纤维肉瘤、低级别纤维黏液样肉瘤、黏液样脂肪肉瘤及黏液样滑膜肉瘤相鉴别。
