炎性肌纤维母细胞瘤

炎性肌纤维母细胞瘤（IMT）是近年被认识和正式命名的独立的中间型（低度恶性）肿瘤,涵盖了以往从炎性反应性病变到肿瘤的一系列诊断.发生于肺和全身各处,表现局部肿块,可伴有发热、体重减轻、盗汗及淋巴结肿大等全身症状.病变以单发或多灶发生,局部浸润性生长,侵犯血管,局部复发,少数病程进展快而致死;较大肿块局部浸润性生长临床和影像学颇似恶性肿瘤.组织学显示炎症背景下不同数量纤维母细胞、肌纤维母细胞、淋巴细胞、浆细胞、嗜酸性粒细胞和组织细胞,间质为粘液性、纤维血管性或胶原性.病变可类似炎症性反应性增生,也可出现坏死、细胞异型增生易与梭形细胞肉瘤/癌混淆.真正病因尚不清楚,已证实肿瘤内肌纤维母细胞有间变性淋巴瘤激酶（ALK）基因重排和表达,并有ALK基因与Rb-2蛋白基因的融合,证实肿瘤性增生本质.本文对该病的认识过程、遗传学研究、病理学、影像学及临床行为做一综述.

Inflammatory Myofibroblastic Tumor

Inflammatory myofibroblastic tumor (IMT) has been recognized and formally described as an intermediate type of tumor with low potential malignancy,comprising a range of diagnoses from pathological changes involved in inflammatory reactions to tumors. It is found in all parts of the human body,usually presenting with a clinical manifestation of a local lump and general symptoms such as fever,weight loss,night sweats and lymphadenectasis,etc. It has unifocal or multifocal symptoms with a capacity for regional infiltrative growth,vascular invasion,local recurrence and even rapid development,causing accelerated death in a few cases. The tumors can be of considerable size and are capable of infiltrative growth,mimicking a malignant tumor clinically and radiologically. Myofibroblast,lymphocyte,plasmocyte,eosinophil granulocyte,histiocyte,mucous interstitium,and vascular or collagenous fiber in varying amounts can be found microscopically. These features mimic inflammatory reactive hyperplasia and also,but less so,necrosis,cellular dysplasia and fascicular sarcoma. The exact etiology of this lesion is unknown. There is expression of anaplastic lymphoma kinase (ALK) in IMT resulting from a fusion of the ALK gene to the Ran-binding protein 2 (RANBP2) gene. The diagnostic process,genetics,pathology,radiology,and clinical behavior of IMT is described herein.