Hatakeyama Hiromitsu, Hoshino Kimiko, Mizoguchi Kenji, Suzuki Takayoshi, Hatanaka Kanako C, Yamaya Yukie, Kano Satoshi, Mizumachi Takatsugu, Homma Akihiro
Department of Otolaryngology-Head and Neck Surgery, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-ku, Sapporo, 060-8638, Japan.
Department of Surgical Pathology, Hokkaido University Graduate School of Medicine, Kita 15, Nishi 7, Kita-ku, Sapporo, 060-8638, Japan.
Diagn Cytopathol. 2017 Oct;45(10):928-933. doi: 10.1002/dc.23751. Epub 2017 May 22.
Atypical adenoma of the thyroid is a rare form of tumor, and its accurate diagnosis prior to surgical resection is difficult as the histological and pathological morphologies are very similar to those of anaplastic thyroid carcinoma (ATC), and its anaplastic transformation remains to be elucidated. We reported a case of a 75-year-old female with a thyroid isthmus nodule diagnosed repeatedly by FNAC as anaplastic carcinoma. Both the first and second FNAC specimen slides showed a large number of scattered or aggregated atypical cells consisting of large, pleomorphic nuclei with irregular membranes, chromatin clumps and prominent nucleoli. The morphology of the surgical specimen was similar to that of an anaplastic carcinoma and although it showed signs of transition from a normal follicular epithelium, there was no invasive growth or mitosis. This lesion was diagnosed as an atypical adenoma, and a papillary carcinoma was also present in the right lobe of the thyroid. Here we evaluate the molecular features of atypical adenomas in comparison with 9 ATC samples, and discuss whether or not atypical adenomas represent a form of premalignant lesion. Ki-67 expression was found to be very low in atypical adenomas whereas all ATC samples showed high levels of Ki-67 expression. Epithelial-mesenchymal transition (EMT) marker expression suggested that atypical adenomas maintain their epithelial phenotype to a higher degree than do ATCs. Differential diagnosis between ATC and atypical adenoma is difficult by cytological and histological methods alone, and Ki-67 and EMT marker expression may support the diagnosis.
甲状腺非典型腺瘤是一种罕见的肿瘤形式，由于其组织学和病理形态与间变性甲状腺癌（ATC）非常相似，在手术切除前准确诊断很困难，其间变性转变仍有待阐明。我们报告了一例75岁女性，其甲状腺峡部结节经细针穿刺抽吸活检（FNAC）多次诊断为间变性癌。第一次和第二次FNAC标本玻片均显示大量散在或聚集的非典型细胞，这些细胞由大的、多形性核组成，核膜不规则、染色质团块和明显的核仁。手术标本的形态与间变性癌相似，尽管它显示出从正常滤泡上皮转变的迹象，但没有浸润性生长或有丝分裂。该病变被诊断为非典型腺瘤，甲状腺右叶还存在乳头状癌。在此，我们将非典型腺瘤的分子特征与9个ATC样本进行比较，并讨论非典型腺瘤是否代表一种癌前病变形式。发现非典型腺瘤中Ki-67表达非常低，而所有ATC样本均显示高水平的Ki-67表达。上皮-间质转化（EMT）标志物表达表明，非典型腺瘤比ATC更能维持其上皮表型。仅通过细胞学和组织学方法难以鉴别ATC和非典型腺瘤，Ki-67和EMT标志物表达可能有助于诊断。
