Papillary thyroid carcinoma is the most common thyroid carcinoma and has a generally favorable prognosis. There are several well-characterized variants, some of which are associated with more aggressive clinical behavior. Hobnail is a recently described rare variant that appears to behave more aggressively. Initial reports characterizing this variant focused on primary tumors and excluded other recognized variants, as well as poorly differentiated and anaplastic thyroid carcinomas, from analysis. Here, we evaluate the frequency of hobnail features in both primary and metastatic papillary thyroid carcinomas, including in association with other known variants, and also in poorly differentiated and anaplastic thyroid carcinomas. Primary and metastatic papillary thyroid carcinomas from a 5-year period (2007 to 2011) and all available anaplastic and poorly differentiated thyroid carcinomas from a 22-year period (1989 to 2011) were retrieved from the files. Tumors from 478 papillary, 26 anaplastic, and 18 poorly differentiated thyroid carcinomas were reviewed for hobnail features present in >10% of each tumor. Hobnail features were most commonly observed in association with poorly differentiated thyroid carcinoma (4 of 18 cases, 22%) and were seen in only 1.3% of papillary thyroid carcinoma patients (6 of 478). One of 26 anaplastic carcinomas had hobnail features (3.8%). Among the papillary thyroid carcinomas, hobnail features were often associated with other histologic variants that are known to be more clinically aggressive, had increased mitotic activity, and/or necrosis and lymph node metastases at presentation. These findings suggest that hobnail features may be a manifestation of higher-grade transformation.
甲状腺乳头状癌是最常见的甲状腺癌，预后一般较好。它有多种熟知的亚型，一些亚型与临床行为更具侵袭性有关。鞋钉亚型是一种新近被描述的亚型，更具侵袭性。最初对该亚型的研究集中在分析肿瘤本身并除外其它已知的PTC亚型和低分化癌及间变性甲状腺癌。在此，我们评估原发性及转移性PTC、低分化癌和间变性甲状腺癌中鞋钉特点发生状况，以及与其它已知PTC亚型间关系。回顾性收集了5年期间(2007 to 2011) 的原发性及转移性PTC和22年期间 (1989 to 2011) 的低分化癌和间变性癌资料。478例PTC, 26例间变性癌, 18例低分化癌每一个肿瘤有>10%的出现鞋钉特点。 鞋钉特点最常见于低分化甲状腺癌(4/18, 22%)，仅见于1.3% 的PTC (6/478)，1/26例(3.8%) 间变性癌有鞋钉特点。PTC中，鞋钉特点常见于具有如下特点的组织学亚型：更富侵袭性、核分裂活性高、伴坏死、发现时有淋巴结转移。这些结果提示鞋钉特点可能是肿瘤向高级别转化的表现。