Section of Endocrine Surgery, Department of General, Visceral and Transplantation Surgery, University Medicine Mainz, Langenbeckstraße 1, 55131, Mainz, Germany.
Best Pract Res Clin Endocrinol Metab. 2019 Aug;33(4):101292. doi: 10.1016/j.beem.2019.101292. Epub 2019 Jul 9.
Follicular thyroid carcinoma is the second most prevalent form of differentiated thyroid carcinoma, following papillary thyroid carcinoma. Preoperative diagnosis is hampered by the fact that fine-needle aspiration cytology as well as supplemental molecular analysis cannot unambiguously distinguish between follicular thyroid carcinoma and benign follicular thyroid adenoma. The 2017 WHO classification defines three histological subtypes of follicular thyroid carcinoma: minimally invasive (excellent prognosis), encapsulated angioinvasive, and widely invasive type (higher risk of recurrence and metastatic spread). The fact that definite characterization of follicular neoplasms is predominantly a postoperative histological diagnosis (core criteria: capsular, vascular and adjacent tissue invasion) translates into the challenge for the thyroid surgeon to plan preoperatively for presence of malignancy and, if required, to adapt the surgical strategy according to intraoperative (frozen section) or postoperative histological findings. Until improved tools for pre-/intraoperative diagnosis are available, the malignant potential of a follicular thyroid lesion can be assessed by stratifying the patient according to clinical risk factors (presence of metastases, advanced patient age, tumor size). A stepwise, escalating surgical approach with restricted primary resection (hemithyroidectomy) and completion surgery based on the definite histopathology is another option to solve this dilemma. The currently recommended surgical treatment strategies for FTCs as published by ATA, BTA, CAEK and ESES are discussed. There is consensus that prophylactic lymphadenectomy is not required for FTCs and that hemithyroidectomy is sufficient in low-risk FTCs (capsular invasion only) whereas thyroidectomy with postoperative radioiodine therapy is indicated in high-risk FTCs (angioinvasion; widely invasive FTC).
滤泡状甲状腺癌是仅次于甲状腺乳头状癌的第二大常见分化型甲状腺癌。术前诊断受到以下因素的阻碍：细针穿刺细胞学检查以及补充的分子分析无法明确区分滤泡状甲状腺癌和良性滤泡状甲状腺腺瘤。2017 年 WHO 分类定义了三种滤泡状甲状腺癌的组织学亚型：微侵袭型（预后良好）、包裹性血管侵袭型和广泛侵袭型（复发和转移扩散风险较高）。滤泡性肿瘤的明确特征主要是术后组织学诊断（核心标准：包膜、血管和邻近组织侵犯），这给甲状腺外科医生带来了挑战，需要在术前根据恶性肿瘤的存在情况进行规划，如果需要，根据术中（冷冻切片）或术后组织学发现调整手术策略。在有更好的术前/术中诊断工具之前，可以根据临床危险因素（转移、患者年龄较大、肿瘤大小）对患者进行分层，评估滤泡性甲状腺病变的恶性潜能。另一种解决这一困境的方法是采用逐步升级的手术方法，限制初次切除（半甲状腺切除术），并根据明确的组织病理学进行完成手术。ATA、BTA、CAEK 和 ESES 发表的目前推荐的 FTC 手术治疗策略进行了讨论。共识认为，FTC 不需要预防性淋巴结清扫，低危 FTC（仅包膜侵犯）行半甲状腺切除术即可，高危 FTC（血管侵犯；广泛侵袭性 FTC）行甲状腺切除术并术后放射性碘治疗。
