Department of Clinical Pathology, Vejle Hospital, Vejle, Denmark.
Histol Histopathol. 2013 May;28(5):565-84. doi: 10.14670/HH-28.565. Epub 2012 Dec 24.
During the first decade of the 21st century, IgG4-related disease (IgG4-RD), a fibroinflammatory condition occurring at multiple sites of the body, has been newly recognized. As indicated by its name, elevation of IgG4 in the serum and tissue is a common denominator of IgG4-RD. Since the observation that many patients suffering from autoimmune pancreatitis (AIP), a specific type of chronic pancreatitis, had elevated serum levels of IgG4, it was reported that these patients also had increased numbers of IgG4-positive cells in the inflamed pancreatic tissue. In 2003, it was noted that a significant proportion of the AIP patients had a variety of extrapancreatic fibroinflammatory lesions, and that AIP therefore was the pancreatic manifestation of a systemic disease. Among these extrapancreatic manifestations, the extrahepatic bile ducts, salivary glands, thyroid, lymph nodes and retroperitoneum were most frequently reported, and infiltration of the tissue with IgG4-positive cells was also noted at these sites. During the following years, a multitude of other conditions have been added to the spectrum of IgG4-RD. While some of these organ manifestations were once believed to represent diseases on their own, others have been included under the umbrella of "multifocal fibrosclerosis". Biopsies or resection specimens from affected organs in IgG4-RD reveal several common microscopic features irrespective of the site of the lesion. Cellular and storiform fibrosis, lymphoplasmacytic infiltration, increased numbers of IgG4-positive cells and obliterative phlebitis are among the most characteristic histological changes in IgG4-RD. The detailed etiology, pathophysiology, epidemiology and clinical long-term outcome have at present yet to be fully elucidated. This paper focuses on the microscopic features, diagnosis and differential diagnosis of the different organ manifestations of IgG4-RD, and the current concepts of its pathogenesis will also be addressed.
在 21 世纪的第一个十年中，IgG4 相关疾病（IgG4-RD）作为一种发生在身体多个部位的纤维炎症性疾病，已被新认识到。顾名思义，血清和组织中 IgG4 的升高是 IgG4-RD 的共同特征。由于观察到许多患有自身免疫性胰腺炎（AIP）的患者，即一种特定类型的慢性胰腺炎，其血清 IgG4 水平升高，因此报告称这些患者的炎症胰腺组织中也有更多数量的 IgG4 阳性细胞。2003 年，人们注意到相当一部分 AIP 患者有多种胰外纤维炎症性病变，因此 AIP 是全身性疾病的胰腺表现。在这些胰外表现中，肝外胆管、唾液腺、甲状腺、淋巴结和腹膜后腔最常被报道，并且在这些部位也观察到组织中 IgG4 阳性细胞的浸润。在随后的几年中，又有许多其他疾病被纳入 IgG4-RD 的范畴。虽然其中一些器官表现曾经被认为是独立的疾病，但其他疾病已被归入“多灶性纤维硬化症”的范畴。在 IgG4-RD 中，受累器官的活检或切除标本无论病变部位如何，都显示出一些共同的显微镜特征。细胞性和席纹状纤维化、淋巴浆细胞浸润、IgG4 阳性细胞数量增加和闭塞性静脉炎是 IgG4-RD 最具特征性的组织学改变之一。其详细的病因、病理生理学、流行病学和临床长期预后目前尚未完全阐明。本文重点介绍 IgG4-RD 不同器官表现的显微镜特征、诊断和鉴别诊断，以及其发病机制的当前概念。
