Deshpande Vikram
Departments of Pathology, Massachusetts General Hospital and Harvard Medical School, Warren 2/55 Fruit Street, Boston, MA, 02114, USA,
Head Neck Pathol. 2015 Mar;9(1):24-31. doi: 10.1007/s12105-015-0620-6. Epub 2015 Mar 25.
IgG4 related disease of the head and neck region represents one of the more common manifestations of IgG4 related disease. Involvement of the submandibular and parotid glands, the orbit and thyroid represent some of the more common sites involved by IgG4 related disease. Eosinophilic angiocentric fibrosis, Mikulicz disease and Riedel thyroiditis are also members of the family of IgG4 related disease. Clinically, the disease is characterized by tumefactive lesions, often multicentric, that show a swift response to immunosuppressive therapy. An elevated serum IgG4 represents the only validated blood based biomarker. However, elevated serum IgG4 is detected in only half the patients with this disease. Histology continues to represent the gold standard for the diagnosis of IgG4 related disease: storiform-type fibrosis and obliterative phlebitis constitute characteristic features of this disease. A definitive diagnosis of IgG4 related disease also requires the presence of elevated numbers of IgG4 positive plasma cells as well as an IgG4 to IgG ratio of greater than 40 %. In isolation, elevated numbers of IgG4 positive plasma cells represents a non-specific feature, detected in a variety of other inflammatory as well as neoplastic diseases. Attention to the clinical context, histological features, as well as an elevated IgG4 to IgG ratio is critical to avoiding overdiagnosis of IgG4 related disease.
头颈部IgG4相关疾病是IgG4相关疾病较常见的表现形式之一。下颌下腺、腮腺、眼眶和甲状腺受累是IgG4相关疾病较常见的受累部位。嗜酸性粒细胞性血管中心性纤维化、米库利奇病和里德尔甲状腺炎也是IgG4相关疾病家族的成员。临床上，该疾病的特征是肿块样病变，通常为多中心性，对免疫抑制治疗反应迅速。血清IgG4升高是唯一经过验证的基于血液的生物标志物。然而，仅一半的该疾病患者可检测到血清IgG4升高。组织学仍是诊断IgG4相关疾病的金标准：席纹状纤维化和闭塞性静脉炎是该疾病的特征性表现。IgG4相关疾病的确切诊断还需要IgG4阳性浆细胞数量增多以及IgG4与IgG的比例大于40%。单独出现IgG4阳性浆细胞数量增多是一种非特异性表现，在多种其他炎症性疾病以及肿瘤性疾病中均可检测到。关注临床背景、组织学特征以及IgG4与IgG的比例对于避免IgG4相关疾病的过度诊断至关重要。
