Sakai Yasuhiro, Imamura Yoshiaki
Department of Tumor Pathology, Faculty of Medical Sciences, University of Fukui, 23-3 Matsuoka-Shimoaizuki, Eiheiji, Fukui, 910-1193, Japan.
Division of Diagnostic Pathology/Surgical Pathology, University of Fukui Hospital, Eiheiji, Japan.
Diagn Pathol. 2018 Jan 3;13(1):3. doi: 10.1186/s13000-017-0681-9.
It has been recently accepted that IgG4-related thyroiditis is comparable to the Hashimoto and Riedel thyroiditis and Graves disease which are rich in IgG4-secreting plasma cells. Many physicians believe that in IgG4-related thyroiditis, the thyroid is entirely enlarged and diffusely affected, which is similar to conventional thyroiditis, but rarely ever accompanied by pseudoneoplastic mass formation as in IgG4-related disease in the other organs. This report introduces another pattern of IgG4-related thyroiditis as mass-forming thyroiditis and presents the occurrence of IgG4-related regional lymphadenopathy as an unusual accompanying symptom.
A 66-year-old woman presented with an approximately 2.5-cm mass in the right thyroidal lobe and regional lymph node swelling, which were preoperatively misinterpreted as thyroidal carcinoma. After lobectomy, histological examination was performed, revealing that the mass showed dense stromal fibrosis, lymphoplasmacytic infiltration, and effacement of thyroid follicles, while the background thyroidal tissue seemed to mimic lymphocytic thyroiditis without fibrosis. Immunohistochemistry revealed predominance of IgG4-secreting plasma cells among infiltrating lymphocytes independent of mass lesion or background tissue. In addition, the regional Delphian and paratracheal lymph nodes were swollen, histologically showing numerous IgG4-secreting plasma cell infiltrations in the interfollicular zone.
IgG4-related mass-forming thyroiditis, which may be an extremely rare but recognizable pattern of IgG4-related thyroiditis, may be distinguishable from Hashimoto and Riedel thyroiditis, Graves disease, and thyroidal carcinoma. In addition, the regional IgG4-related lymphadenopathy, also possibly misdiagnosed as metastatic thyroidal carcinoma, may be a newly recognized manifestation of IgG4-related thyroiditis.
最近人们已认识到，IgG4相关性甲状腺炎与桥本甲状腺炎、里德尔甲状腺炎以及富含分泌IgG4的浆细胞的格雷夫斯病具有可比性。许多医生认为，在IgG4相关性甲状腺炎中，甲状腺会整体肿大且呈弥漫性受累，这与传统甲状腺炎相似，但很少像其他器官的IgG4相关性疾病那样伴有假肿瘤性肿块形成。本报告介绍了IgG4相关性甲状腺炎的另一种模式，即形成肿块性甲状腺炎，并呈现出IgG4相关性区域淋巴结病这一不寻常的伴随症状。
一名66岁女性患者，右侧甲状腺叶出现一个约2.5厘米的肿块以及区域淋巴结肿大，术前被误诊为甲状腺癌。肺叶切除术后进行了组织学检查，结果显示肿块表现为致密的间质纤维化、淋巴细胞浆细胞浸润以及甲状腺滤泡消失，而背景甲状腺组织似乎类似无纤维化的淋巴细胞性甲状腺炎。免疫组化显示，在浸润淋巴细胞中，分泌IgG4的浆细胞占优势，与肿块病变或背景组织无关。此外，区域的德尔菲恩淋巴结和气管旁淋巴结肿大，组织学检查显示滤泡间区有大量分泌IgG4的浆细胞浸润。
IgG4相关性形成肿块性甲状腺炎可能是IgG4相关性甲状腺炎一种极其罕见但可识别的模式，可能与桥本甲状腺炎、里德尔甲状腺炎、格雷夫斯病以及甲状腺癌相鉴别。此外，区域IgG4相关性淋巴结病也可能被误诊为转移性甲状腺癌，它可能是IgG4相关性甲状腺炎一种新认识的表现形式。
