BACKGROUND Thyroid cancer accounts for 1% of cancer cases in developed countries, in which papillary thyroid carcinoma (PTC) is the most common type. There are multiple variants of PTC described to date, some of them with aggressive behavior and poor clinical outcome. These variants are well described and accepted in recent guidelines of many international societies, and the prognostic and management implications are well laid out. Due to their established clinical importance and to guide appropriate surgical management, it is now imperative in clinical practice, including cytopathology, to differentiate aggressive variants from nonaggressive ones. This review aims to describe the variants of PTC and to provide a practical algorithmic approach to facilitate the cytological diagnosis of these variants. SUMMARY Subtyping PTC variants on fine needle aspiration cytology (FNAC) is challenging even for the most experienced cytopathologist. To facilitate a correct subtyping on FNAC, we propose a stepwise approach that is mainly designed for conventional smear methodology. This approach requires first to stratify the lesions into oncocytic and nononcocytic features before analyzing further details in cell morphology and pattern. Key Messages: (1) Subtyping in PTC is possible on cytopathology. (2) The main aim of the cytopathologist is to differentiate aggressive from nonaggressive variants. (3) The subtyping of PTC can help in the surgical management of the patients.

中文翻译：

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乳头状甲状腺癌的变种：一种基于细胞形态学算法的细胞学标本方法。

背景技术在发达国家，甲状腺癌占癌症病例的1％，其中乳头状甲状腺癌（PTC）是最常见的类型。迄今为止，描述了PTC的多种变体，其中有些具有攻击性行为且临床效果差。这些变体在许多国际社会的最新指南中得到了很好的描述和接受，并且对预后和管理的意义也作了很好的阐述。由于其已确立的临床重要性并能指导适当的外科治疗，因此在临床实践（包括细胞病理学）中，必须将攻击性变异与非攻击性变异区分开来。这篇综述旨在描述PTC的变异，并提供一种实用的算法方法来促进这些变异的细胞学诊断。总结即使对于最有经验的细胞病理学家，在细针穿刺细胞学（FNAC）上对PTC变体进行分型也是一项挑战。为了促进对FNAC的正确分型，我们提出了一种逐步设计的方法，该方法主要设计用于常规涂片方法。这种方法需要首先在将细胞形态和模式进一步分析之前，先将病变分为包囊和非包囊特征。关键信息：（1）PTC在细胞病理学上可能是亚型的。（2）细胞病理学家的主要目的是区分攻击性和非攻击性变异。（3）PTC的分型可以帮助患者进行手术管理。我们提出一种主要针对常规涂片方法设计的逐步方法。这种方法需要首先在将病灶分为细胞内和非细胞内特征之前将其分层，然后再分析细胞形态和模式的更多细节。关键信息：（1）PTC在细胞病理学上可能是亚型的。（2）细胞病理学家的主要目的是区分攻击性和非攻击性变异。（3）PTC的分型可以帮助患者进行手术管理。我们提出一种主要针对常规涂片方法设计的逐步方法。这种方法需要首先在将细胞形态和模式进一步分析之前，先将病变分为包囊和非包囊特征。关键信息：（1）PTC在细胞病理学上可能是亚型的。（2）细胞病理学家的主要目的是区分攻击性和非攻击性变异。（3）PTC的分型可以帮助患者进行手术管理。