Takahito Ando, Fujii Kimihito, Banno Hirona, Saito Masayuki, Ito Yukie, Ido Mirai, Goto Manami, Mouri Yukako, Kousaka Junko, Imai Tsuneo, Nakano Shogo
Division of Breast and Endocrine Surgery, Department of Surgery, Aichi Medical University, Nagakute, JPN.
Cureus. 2024 Mar 18;16(3):e56404. doi: 10.7759/cureus.56404. eCollection 2024 Mar.
Clinicians sometimes encounter papillary thyroid microcarcinoma (PMC) that is less than 10 mm, associated with lymph node metastasis. In this study, we assessed PMC clinicopathologically to clarify risk factors for poor prognosis.
Fifty-one patients who underwent thyroid surgery at Aichi Medical University from September 2009 to October 2016 were included. Patients were divided into two groups, pEX-positive (23 patients) and pEX-negative (28 patients), based on the pathological finding of thyroid capsule invasion. The former indicates that the tumor infiltrated the thyroid capsule and spread to the neighboring tissue, and the latter indicates no capsule invasion. We analyzed factors such as patient characteristics, pathological findings, and serum levels of thyroid hormones in the two groups.
No statistical differences were observed between the two groups in gender distribution or age at surgery. Preoperative cancer diagnoses were established for more patients in the pEX-positive group than in the pEX-negative group (n = 21 and 14, respectively; P = 0.004). The mean (±SD) pathological tumor diameter was 5.42 ± 2.77 in the pEX-negative group and 8.32 ± 1.61 in the pEX-positive group (P < 0.001). No significant differences in preoperative serum levels of free T3, free T4, thyroid-stimulating hormone, or thyroglobulin were observed between the two groups. The odds ratio for node positivity in tumors invading thyroid capsules (pEX-positive) compared to those with no capsule invasion (pEX-negative) was 13.20 (95% confidence interval, 3.45-50.42). Immunohistological staining for phosphatase and tensin homolog deleted from chromosome 10 (PTEN) and Akt (protein kinase B) revealed the facilitation of PTEN and suppression of Akt, which might indicate downregulation of the phosphoinositide 3-kinase-Akt (PI3K-Akt) cascade.
In general, the prognosis of PMC is favorable. However, the prognosis is less favorable in patients with nodal metastasis or extrathyroidal invasion. It is controversial whether resection is required for proven PMCs. For PMCs associated with extrathyroidal invasion, regional lymph node resection with lobectomy should be performed due to the high risk for lymphatic spread. There might be a possibility that the natural progression of PMC seems to be controlled by the facilitation of PTEN. However, a tumor in the lateral peripheral region of the thyroid parenchyma might be associated with capsule invasion followed by lymphatic spread.
临床医生有时会遇到直径小于10mm且伴有淋巴结转移的甲状腺微小乳头状癌（PMC）。在本研究中，我们对PMC进行了临床病理评估，以明确预后不良的危险因素。
纳入2009年9月至2016年10月在爱知医科大学接受甲状腺手术的51例患者。根据甲状腺被膜侵犯的病理结果，将患者分为两组，pEX阳性组（23例）和pEX阴性组（28例）。前者表明肿瘤浸润甲状腺被膜并扩散至邻近组织，后者表明无被膜侵犯。我们分析了两组患者的特征、病理结果及甲状腺激素血清水平等因素。
两组在性别分布或手术年龄方面未观察到统计学差异。pEX阳性组术前确诊癌症的患者比pEX阴性组更多（分别为21例和14例；P = 0.004）。pEX阴性组病理肿瘤平均直径（±标准差）为5.42±2.77，pEX阳性组为8.32±1.61（P < 0.001）。两组术前血清游离T3、游离T4、促甲状腺激素或甲状腺球蛋白水平均未观察到显著差异。与无被膜侵犯（pEX阴性）的肿瘤相比，侵犯甲状腺被膜（pEX阳性）的肿瘤淋巴结阳性的优势比为13.20（95%置信区间，3.45 - 50.42）。对第10号染色体缺失的磷酸酶和张力蛋白同源物（PTEN）及Akt（蛋白激酶B）进行免疫组织化学染色，显示PTEN增强而Akt受抑制，这可能表明磷酸肌醇3激酶 - Akt（PI3K - Akt）级联反应下调。
一般来说，PMC的预后良好。然而，有淋巴结转移或甲状腺外侵犯的患者预后较差。对于已确诊的PMC是否需要进行切除存在争议。对于伴有甲状腺外侵犯的PMC，由于淋巴转移风险高，应行区域淋巴结清扫术加甲状腺叶切除术。PMC的自然进展可能受PTEN增强的控制。然而，甲状腺实质外侧周边区域的肿瘤可能与被膜侵犯及随后的淋巴转移有关。
