鼻腔鼻窦炎性肌纤维母细胞瘤的临床病理学分析

Clinicopathologic study of sinonasal inflammatory myofibroblastic tumor

目的探讨鼻腔鼻窦炎性肌纤维母细胞瘤（IMT）的临床病理学特征、免疫表型及超微结构特点。方法分析5例鼻腔鼻窦IMT的临床和病理形态学特点，用波形蛋白、肌特异性肌动蛋白（MSA）、平滑肌肌动蛋白（SMA）、钙调节蛋白（calponin）、h-钙结合蛋白（h-caldesmon）、结蛋白、间变性淋巴瘤激酶（ALK）、纤连蛋白（FN）、CK、S一100蛋白、Ki-67等抗体进行免疫组织化学（sP法）标记，取2例做透射电镜观察。结果患者发病年龄28～62岁（平均年龄43岁），男性2例，女性3例，临床表现有鼻堵、流涕，面部疼痛、肿胀，牙疼、溢泪等，1例表现为鼻出血。5例均有复发，4例复发5次以上，1例淋巴结转移，3例死亡。组织学改变：肿瘤细胞排列呈编织状、束状、部分杂乱无序，细胞呈长梭形，有嗜酸性胞质，异型性不明显，核分裂象较少，问质内有较多淋巴细胞、浆细胞浸润，部分间质黏液变性，富于血管，部分区可见透明样变的胶原束。3例多次复发后肿瘤细胞异型性明显，核分裂象增多（平均5～6个／10HPF），可见小灶状坏死，间质内炎性细胞减少，呈肉瘤改变。免疫组织化学标记显示：5例瘤细胞均弥漫表达波形蛋白，不同程度表达SMA、MSA、calponin和FN，结蛋白仅1例弱阳性，h-caldesmon、ALK、S一100蛋白、CK均为阴性，反复复发后Ki-67示瘤细胞增殖指数增高。电镜显示：瘤细胞胞质内可见较多的粗面内质网，部分瘤细胞的胞质内可见密体和密斑的肌丝束，细胞外基质中见多量的胶原纤维。结论鼻腔鼻窦IMT易复发，有局部侵袭性，反复复发后可恶变及转移，病死率高，预后差。完整切除肿瘤是治疗的关键。

Objective To study the clinicopathologic features, immunophenotype and uhrastructural features of sinonasal inflammatory myofibroblastic tumors （IMT）. Methods The clinical and histologic features of 5 cases of sinonasal IMT were reviewed. Immunohistochemical study for vimentin, MSA, SMA, calponin, h-caldesmon, desmin, ALK, fibronectin, CK, S-100 and Ki-67 was carried out. Ultrastructural examination was also performed in two of the cases. Results The patients age ranged from 28 to 62 years （mean = 43 years）. The male-to-female ratio was 2： 3. The clinical presentation included nasal obstruction, nasal discharge, nasal bleeding, facial pain, facial swelling, toothache and tear overflow. All of the 5 patients suffered from disease relapses ; and 4 of them had recurrences for more than 5 times. One patient had lymph node metastasis and 3 patients died of the disease. Histologically, the tumor cells were arranged in interlacing fascicles and sometimes haphazard in fashion. They were spindly in shape, cytoplasm eosinophilic with mild nuclear atypia and a low mitotic activity. The intervening stroma was myxoid in appearance accompanied by lymphocyte and plasma cell infiltration, abundant blood vessels and focal collagenized areas. In 3 of the recurrent cases, the tumor ceils displayed increased nuclear atypia and mitotic activity （ average about 5 to 6 per 10 high-power fields）, accompanied by patchy necrosis, less inflammatory cell infiltration and focal sarcomatous changes. Immunohistochemical study showed that the tumor cells were diffusely positive for vimentin. SMA, MSA, calponin and fibronectin were variably expressed. Desmin was weakly positive in 1 case. The staining for h-caldesmon, ALK, S-100 and CK was negative. The Ki-67 proliferation index increased with tumor recurrences. Electron microscopy revealed abundant roughendoplasmic reticulum and dense body formation in the cytoplasm. There were an increased amount of collagen fibers in the stroma. Conclusions IMT rarely occurs in nasal cavity and paranasal sinuses. The tumor is prone to local invasion and recurrences, with subsequent progression to frank malignancy and distant metastasis, resulting in high mortality and poor prognosis. Complete surgical resection remains the main modality of treatment.