Mentzel T, Dry S, Katenkamp D, Fletcher C D
Department of Pathology, University of Jena, Germany.
Am J Surg Pathol. 1998 Oct;22(10):1228-38. doi: 10.1097/00000478-199810000-00008.
The clinicopathologic, immunohistochemical, and ultrastructural features of a seemingly distinctive low-grade spindle cell sarcoma showing myofibroblastic differentiation have been analyzed in a series of 18 patients. The age range of the patients (7 women and 11 men) was 19-72 years (median: 42 years). A painless, enlarging mass was the most common clinical presentation. Five tumors arose in the oral cavity (including four lesions in the tongue), four in the lower extremities and three in the upper extremities, four cases in the abdominal/pelvic cavity, and two on the trunk. Eight soft-tissue cases involved skeletal muscle, three cases were located in perifascial tissues, and two arose in subcutaneous tissue. Tumor size ranged from 1.4 to 17 cm (median: 4 cm); in six cases (of which four were abdominal/pelvic) the lesion was larger than 5 cm. All patients were treated surgically, and four received additional adjunctive therapy. Histologically, most cases were cellular lesions showing a diffusely infiltrative pattern, and were composed of spindle-shaped tumor cells arranged mainly in fascicles. Tumor cells had poorly defined, palely eosinophilic cytoplasm and fusiform nuclei, which were either tapering and wavy or plumper and vesicular with indentations and small inconspicuous nucleoli. Tumor cells were set in a collagenous matrix often with prominent hyalinization. Mild nuclear atypia was noted in 16 cases; in the other 2 cases, and in the metastases of one other lesion, a greater degree of nuclear atypia was seen. In all but one case, the mitotic rate ranged from 1 to 6 mitoses in 10 HPFs (mean: 2/10 HPFs); in a single case, there were more than 20 mitoses in 10 HPFs. Immunohistochemically, all cases stained positively for at least one myogenic marker; 12 cases were positive for desmin, 11 for alpha-smooth muscle actin, and 6 for muscle actin (HHF35). Seven neoplasms were desmin positive/ alpha-smooth-muscle actin negative, and five cases were desmin negative/alpha-smooth-muscle actin positive emphasizing the variable immunophenotype of myofibroblastic lesions. In addition, 7 of 10 tumors stained at least focally positive for fibronectin. Ultrastructural examination in five cases showed characteristic features of myofibroblasts. Follow-up in 11 patients (median: 29 months) revealed local recurrence in 2 cases, and multiple distant soft-tissue, intraosseous, and pulmonary metastases in one other patient. Low-grade myofibroblastic sarcoma seems to represent a distinct entity in the spectrum of low-grade myofibroblastic neoplasms and is distinguishable from fibromatosis, myofibromatosis, solitary fibrous tumor, fibrosarcoma, and leiomyosarcoma.
对一系列18例表现为肌成纤维细胞分化的看似独特的低级别梭形细胞肉瘤的临床病理、免疫组化及超微结构特征进行了分析。患者年龄范围为19 - 72岁（中位数：42岁），其中女性7例，男性11例。无痛性肿块增大是最常见的临床表现。5例肿瘤发生于口腔（包括舌部4个病灶），4例发生于下肢，3例发生于上肢，4例发生于腹腔/盆腔，2例发生于躯干。8例软组织病例累及骨骼肌，3例位于筋膜周围组织，2例发生于皮下组织。肿瘤大小为1.4至17厘米（中位数：4厘米）；6例（其中4例为腹腔/盆腔肿瘤）病灶大于5厘米。所有患者均接受手术治疗，4例接受了额外的辅助治疗。组织学上，大多数病例为细胞性病变，呈弥漫浸润性生长模式，由主要排列成束状的梭形肿瘤细胞组成。肿瘤细胞胞质界限不清，淡嗜酸性，核呈梭形，要么逐渐变细且呈波浪状，要么更饱满呈泡状，有切迹和小而不明显的核仁。肿瘤细胞位于胶原基质中，常伴有明显的玻璃样变。16例可见轻度核异型性；另外2例以及另一例病变的转移灶可见更明显的核异型性。除1例病例外，其余病例的有丝分裂率为每10个高倍视野1至6个有丝分裂象（平均：2/10高倍视野）；1例病例每10个高倍视野有丝分裂象超过20个。免疫组化方面，所有病例至少对一种肌源性标志物呈阳性染色；12例结蛋白阳性，11例α - 平滑肌肌动蛋白阳性，6例肌动蛋白（HHF35）阳性。7例肿瘤结蛋白阳性/α - 平滑肌肌动蛋白阴性，5例结蛋白阴性/α - 平滑肌肌动蛋白阳性，强调了肌成纤维细胞性病变免疫表型的多样性。此外，10例肿瘤中有7例至少局灶性地对纤连蛋白呈阳性染色。5例病例的超微结构检查显示了肌成纤维细胞的特征性表现。11例患者（中位数：29个月）的随访显示，2例局部复发，另一例患者出现多处远处软组织、骨内及肺转移。低级别肌成纤维细胞肉瘤似乎是低级别肌成纤维细胞性肿瘤谱中的一个独特实体，可与纤维瘤病、肌纤维瘤病、孤立性纤维性肿瘤、纤维肉瘤和平滑肌肉瘤相鉴别。
