肢端黏液炎性纤维母细胞性肉瘤

目的 探讨肢端黏液炎性纤维母细胞性肉瘤的临床病理学特征、免疫学表型及其鉴别诊断。方法 对1例发生于足背和右小腿远端的肢端黏液炎性纤维母细胞性肉瘤进行光镜观察和免疫组化标记。结果 患者因足背皮下“结节性筋膜炎”局部切除术后复发就诊。体检发现足背至右小腿远端前外侧皮下多发性结节,直径1～4cm,影像学检查提示肿瘤累及深部骨膜。镜下肿瘤由比例不等的黏液样区、透明变性区及炎症性区域混合组成。黏液样区域主要由交织条柬状排列的梭形瘤细胞组成,核显示轻至中度异型性,核分裂象罕见,间质疏松、黏液样,局部区域可见黏液湖形成。其内可见单空泡印戒样或多空泡状假脂肪母细胞,形态类似黏液纤维肉瘤。透明样区域由散在的胖梭形至卵圆形的瘤细胞和透明样间质混和组成。炎症性区域由成簇的淋巴细胞组成,与黏液样区域和透明变性区相混杂。病变内可见体积较大类似节细胞或R-S细胞的畸形细胞。免疫组化标记显示瘤细胞弥漫表达Vim,个别细胞表达p53,而CD68、actin、Des、CD34、CD30和S-100蛋白等标记均为阴性,多数淋巴细胞表达CD45RO。结论 肢端黏液炎性纤维母细胞性肉瘤是一种罕见的低度恶性软组织肉瘤,瘤细胞由变异的纤维母细胞衍化而来,熟悉其形态学特征对避免误诊为其它良性或恶性病变具有重要意义。该瘤常在局部呈侵袭性生长,具有较高的复发率,临床上应予以完整切除。

Acral myxoinflammatory fibroblastic sarcoma

Purpose To study the clinicopathological features, immunophenotype and differential diagnosis of acral myxoinflammatory fibroblastic sarcoma (AMIFS). Methods Case of AMIFS in dorsum of right foot and distal part of right lower extremity were studied by light microscopy and immunohistochemistry. Results A patient complained of a recurrent mass located in his right foot dorsum which was initially reported as a "nodular fasciitis". Physical examination revealed multiple nodular masses in the subcutis extending from the dorsum of the foot to the anterolateral side of the lower leg measuring 1cm to 4 cm in diameter. CT displayed involvement of the underlying periosteum. Microscopically, the tumor was characterized by a dense inflammatory infiltrate merging with hyaline and myxoid zones in variable proportions. The myxoid zones were composed of spindle cells arranged in intersecting fascicles in a loose stroma, resembling those of a myxofibrosarcoma. The neoplastic cells exhibited a mild to moderate degree of nuclear atypia with rare mitotic figures. Pool of mucin containing scattered monovacuolated or multivacuolated pseudolipoblast cells were noted in some areas. Hyaline zones were composed of sclerosis and scattered cells in shape from stubby spindle to ovoid, while inflammatory areas were composed of clusters of small lymphocytes. Bizarre ganglion like or Reed Sternberg like cells were occasionally seen. The spindle cells were diffusely positive for vimentin with few expressing p53, but all were negative for CD68, actin, desmin, CD34, CD30, S 100 protein and others. Most lymphocytes showed immunoreactivity to CD45RO. Conclusions Acral myxoinflammatory fibroblastic sarcoma is an extremely rare entity of modified fibroblast cells which should be viewed as a tumor of low grade malignancy. Recognizing its morphological characteristics is important to avoid confusion with other benign or malignant tumors with similar features. As the tumor behaviors aggressively with a high rate of local recurrence, complete excision is recommended.