Grebe S K, Hay I D
Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota, USA.
Endocrinol Metab Clin North Am. 1995 Dec;24(4):761-801.
Follicular thyroid cancer is the second most common thyroid malignancy after PTC. There are marked geographical variations in the relative proportions of FTC and PTC, most likely related to dietary iodine content. In iodine-deficient areas, the relative rate of FTC tends to be increased. Other risk factors for FTC include age over 50 years and female sex. Genetic factors may also have a role in determining disease susceptibility but remain ill-defined. Histologically, FTC is characterized by follicle formation and the absence of any papillary elements in the tumor. Differential diagnosis from a benign adenoma can be difficult. The degree of vascular invasiveness seems to correlate with tumor aggressiveness, and two histologic subtypes, oxyphilic FTC and insular FTC, may be associated with increased morbidity and mortality. Primary treatment for FTC is complete surgical tumor removal. Extensive bilateral surgery beyond this goal may not confer additional benefit but can facilitate adjuvant treatment and follow-up. Postoperative levothyroxine treatment is almost universally used, and patients deemed at high risk of recurrence may benefit from radioiodine remnant ablation. Treatment of metastatic disease involves operation, radioiodine, and, in selected cases, external beam radiation and chemotherapy. Prognosis for patients with metastatic disease is guarded, but most other patients have good outcomes comparable to that in PTC. For nonoxyphilic FTC, high-risk features other than initial metastases include advanced age, locally extensive disease, and the presence of marked angioinvasion. In oxyphilic FTC, DNA aneuploidy is also important. Follow-up should be most intense during the first 5 years after primary treatment and needs to be tailored to the patient's risk of disease progression. For patients at low risk of recurrence (young, small lesions, minimally invasive tumor), serum thyroglobulin measurements may largely suffice, whereas higher risk patients with elevated serum thyroglobulin levels and patients with significant titers of interfering anti-thyroglobulin autoantibodies may also need to undergo periodic diagnostic radioiodine scanning.
滤泡性甲状腺癌是仅次于乳头状甲状腺癌（PTC）的第二常见甲状腺恶性肿瘤。滤泡性甲状腺癌（FTC）和乳头状甲状腺癌（PTC）的相对比例存在显著的地域差异，这很可能与饮食中的碘含量有关。在碘缺乏地区，FTC的相对发病率往往会增加。FTC的其他风险因素包括50岁以上的年龄和女性性别。遗传因素在决定疾病易感性方面可能也起作用，但仍不明确。在组织学上，FTC的特征是形成滤泡，且肿瘤中不存在任何乳头状成分。与良性腺瘤进行鉴别诊断可能很困难。血管侵袭程度似乎与肿瘤侵袭性相关，两种组织学亚型，嗜酸性FTC和岛状FTC，可能与发病率和死亡率增加有关。FTC的主要治疗方法是完整切除肿瘤。超出此目标的广泛双侧手术可能不会带来额外益处，但有助于辅助治疗和随访。术后几乎普遍使用左甲状腺素治疗，被认为复发风险高的患者可能受益于放射性碘残留消融。转移性疾病的治疗包括手术、放射性碘治疗，在某些情况下还包括外照射放疗和化疗。转移性疾病患者的预后不佳，但大多数其他患者的预后良好，与PTC患者相当。对于非嗜酸性FTC，除了初始转移外的高风险特征包括高龄、局部广泛病变和明显的血管侵袭。在嗜酸性FTC中，DNA非整倍体也很重要。随访在初次治疗后的前5年应最为密集，并且需要根据患者疾病进展的风险进行调整。对于复发风险低的患者（年轻、病变小、肿瘤微创），血清甲状腺球蛋白测量可能基本足够，而血清甲状腺球蛋白水平升高的高风险患者以及具有高滴度干扰性抗甲状腺球蛋白自身抗体的患者可能还需要定期进行诊断性放射性碘扫描。
