Despite the interest of researchers in IgG4‐related disease (IgG4‐RD), many questions still remain unanswered regarding the thyroid gland. We aimed to clarify the relationship between IgG4‐positive plasma cells and the histopathological pattern in the Hashimoto thyroiditis (HT) in a Finnish series. HT specimens (n = 280) were retrieved from the Department of Pathology, Fimlab Laboratories. After re‐evaluation, 82 (29%) cases (72 females and 10 males, 52 ± 17 years) with significant fibrosis were selected. CD38, IgG and IgG4 positivity in plasma cells was evaluated by immunohistochemistry. Adjusted IgG4‐positive plasma cells per HPF > 20 and IgG4‐ to IgG‐positive plasma cell ratio > 30% were adopted as threshold criteria and related to other morphological features. IgG4‐positive HT group included 13 cases (15% from fibrotic HT, 4.6% from all HT, 50 ± 15 years, 11 females) with adjusted HPF count 30 ± 5 (23–40) IgG4‐positive cells. IgG4‐positivity significantly correlated with the presence of lobulation, oncocytic metaplasia and certain type of fibrosis, fibrosis spread outside the gland, lymphocytes/plasma cells epithelial penetration, the predominance of microfollicles and follicular atrophy in the present study. Despite the persisting uncertainty whether HT is IgG4‐RD, HT with IgG4‐positive plasma cells is histopathologically distinct entity with some geographic variability.

中文翻译：

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桥本甲状腺炎中IgG4阳性浆细胞：与IgG4相关的疾病还是与炎症相关的IgG4阳性？

尽管研究人员对IgG4相关疾病（IgG4-RD）感兴趣，但有关甲状腺的许多问题仍未得到解答。我们旨在阐明芬兰文系列中桥本甲状腺炎（HT）中IgG4阳性浆细胞与组织病理学模式之间的关系。HT标本（n = 280）从Fimlab Laboratories的病理学系获取。经过重新评估后，选择了82例（29％）纤维化明显的病例（72例女性和10例男性，52±17岁）。通过免疫组织化学评估浆细胞中的CD38，IgG和IgG4阳性。调整后的HPF> 20的IgG4阳性浆细胞和IgG4 / IgG阳性浆细胞比率> 30％被用作阈值标准，并与其他形态学特征有关。IgG4阳性HT组包括13例（15％来自纤维化HT，4。调整后的HPF计数为30±5（23–40）个IgG4阳性细胞，所有HT（50±15岁，11位女性）中的6％。IgG4阳性与小叶的存在，胞浆化生和某些类型的纤维化，纤维化扩散到腺外，淋巴细胞/浆细胞上皮渗透，微囊的优势和滤泡萎缩显着相关。尽管HT是否为IgG4-RD仍存在不确定性，但HT4和IgG4阳性浆细胞是组织病理学上不同的实体，具有一定的地理变异性。本研究中微囊和滤泡萎缩的优势。尽管HT是否为IgG4-RD仍存在不确定性，但HT4和IgG4阳性浆细胞是组织病理学上不同的实体，具有一定的地理变异性。本研究中微囊和滤泡萎缩的优势。尽管HT是否为IgG4-RD仍存在不确定性，但HT4和IgG4阳性浆细胞是组织病理学上不同的实体，具有一定的地理变异性。