Department of Pathology, Ankara University Medical School, Ahmet Adnan Saygun Street No: 35 Sihhiye, 06230, Ankara, Turkey.
Department of Biostatistics, Ankara University Medical School, Ahmet Adnan Saygun Street No: 35 Sihhiye, 06230, Ankara, Turkey.
Endocr Pathol. 2021 Sep;32(3):357-367. doi: 10.1007/s12022-020-09650-1. Epub 2021 Jan 4.
Papillary thyroid carcinoma (PTC) is the most common type of thyroid malignancy. Some PTCs with classical papillae can be totally or partially encapsulated, and these tumors are called "encapsulated" (conventional) variant of papillary thyroid carcinoma. We aimed to investigate the clinicopathological features of this variant, comparing with non-encapsulated conventional type PTC. Among 823 thyroidectomy specimens with PTC diagnosed between 2015 and 2018, 121 tumors from 105 patients (12.75%) were reclassified as encapsulated conventional PTC. In 76 patients, tumors were unifocal. Size, cystic changes, background thyroiditis, psammoma bodies, cervical lymph node metastasis at presentation, capsular/vascular invasion, and immunohistochemical BRAF-V600E expression were evaluated. Ninety-two non-encapsulated conventional PTCs served as control group. Encapsulated cases were predominantly women (73.3%), 56.4% were microcarcinomas, 97.5% had cystic changes, 81.4% were BRAF-V600E positive, and 36.8% of unifocal encapsulated tumors had cervical lymph node metastasis. Thyroiditis and psammoma bodies were detected in nearly half of the encapsulated PTCs. Fourteen percent of the unifocal tumors showed total encapsulation, whereas capsular and vascular invasion was detected in 85.5% and 5.8%, respectively. Encapsulated cases did not show any significant difference from the control group, except for prominent cystic changes (p < 0.001). Relationship between lymph node metastasis at presentation and capsular invasion was statistically significant (p = 0.001), and metastasis was more frequent in cases with extensive capsular invasion (no/minimal invasion versus extensive invasion, p < 0.001). Cystic changes are very common, and this feature deserves mentioning as a morphological characteristic of encapsulated conventional PTCs. As in encapsulated "follicular" variant of PTC, capsular invasion status is important in evaluating papillary patterned encapsulated PTC for predicting lymph node metastasis. Total examination of the tumor capsule and inclusion of capsular invasion status in pathology reports are recommended.
甲状腺乳头状癌（PTC）是最常见的甲状腺恶性肿瘤。一些具有经典乳头结构的 PTC 可以完全或部分被包膜包裹，这些肿瘤被称为“包膜内”（经典型）甲状腺乳头状癌变异型。我们旨在研究该变异型的临床病理特征，并与非包膜内经典型 PTC 进行比较。在 2015 年至 2018 年期间诊断为 PTC 的 823 例甲状腺切除术标本中，有 121 例（12.75%）来自 105 例患者的肿瘤被重新分类为包膜内经典型 PTC。在 76 例患者中，肿瘤为单灶性。评估了肿瘤的大小、囊性变、桥本甲状腺炎、砂粒体、初诊时的颈部淋巴结转移、包膜/血管侵犯和免疫组织化学 BRAF-V600E 表达。92 例非包膜内经典型 PTC 作为对照组。包膜内病例主要为女性（73.3%），56.4%为微癌，97.5%有囊性变，81.4%为 BRAF-V600E 阳性，81.4%为单灶性包膜内肿瘤有颈部淋巴结转移。近一半的包膜内 PTC 检测到桥本甲状腺炎和砂粒体。14%的单灶性肿瘤完全包膜化，而包膜和血管侵犯分别为 85.5%和 5.8%。包膜内病例与对照组相比，除了明显的囊性变（p<0.001）外，没有任何显著差异。初诊时的淋巴结转移与包膜侵犯之间存在统计学显著关系（p=0.001），并且在广泛包膜侵犯的病例中转移更为频繁（无/轻微侵犯与广泛侵犯，p<0.001）。囊性变非常常见，这一特征值得一提，是包膜内经典型 PTC 的形态学特征。与包膜内滤泡型 PTC 一样，包膜侵犯状态对于评估具有乳头状模式的包膜内 PTC 是否有淋巴结转移具有重要意义。建议对肿瘤包膜进行全面检查，并在病理报告中包含包膜侵犯状态。
