Abstract：
OBJECTIVE: Ectopic parathyroid carcinoma (EPC) is a rare clinical entity with multiple diagnostic pitfalls, making surgical cures challenging. We assessed the clinicopathological spectrum and outcome of EPCs.
METHODS: In this retrospective cohort study, 24 EPCs were identified from 133 PC patients treated at a tertiary referral center. The relationship between clinicopathological findings and locations was analyzed.
RESULTS: The locations of EPCs were predominantly intrathyroidal (62.5%), followed by 16.7% in the mediastinum, 8.3% in the retropharyngeal space, 8.3% in the carotid sheath, and 4.2% in the upper neck. Intrathyroidal EPC patients experienced higher serum calcium (p = 0.020), a higher rate of vascular invasion (p = 0.040), and a slightly higher incidence of non-R0 initial resection (p = 0.092) than those in other ectopic locations. Intrathyroidal EPC patients also suffered a trend of higher upper aerodigestive tract (UAT) invasion rate (p = 0.070) and higher risks of distant metastasis (p = 0.037) than the other PC patients. The 5-year disease-free survival rate after surgery was slightly compromised at 41.5% in intrathyroidal EPC patients compared with 77.8% among those in other ectopic locations (p = 0.143) and 59.7% among the other PC patients (log-rank = 3.194; p = 0.074), though without statistical significance.
CONCLUSIONS: Intrathyroidal EPC might cause a more biochemically and invasively distinct PC picture compared with other PCs. Special caution should be exercised in the preoperative diagnosis and management of such cases.
METHODS: In this retrospective cohort study, 24 EPCs were identified from 133 PC patients treated at a tertiary referral center. The relationship between clinicopathological findings and locations was analyzed.
RESULTS: The locations of EPCs were predominantly intrathyroidal (62.5%), followed by 16.7% in the mediastinum, 8.3% in the retropharyngeal space, 8.3% in the carotid sheath, and 4.2% in the upper neck. Intrathyroidal EPC patients experienced higher serum calcium (p = 0.020), a higher rate of vascular invasion (p = 0.040), and a slightly higher incidence of non-R0 initial resection (p = 0.092) than those in other ectopic locations. Intrathyroidal EPC patients also suffered a trend of higher upper aerodigestive tract (UAT) invasion rate (p = 0.070) and higher risks of distant metastasis (p = 0.037) than the other PC patients. The 5-year disease-free survival rate after surgery was slightly compromised at 41.5% in intrathyroidal EPC patients compared with 77.8% among those in other ectopic locations (p = 0.143) and 59.7% among the other PC patients (log-rank = 3.194; p = 0.074), though without statistical significance.
CONCLUSIONS: Intrathyroidal EPC might cause a more biochemically and invasively distinct PC picture compared with other PCs. Special caution should be exercised in the preoperative diagnosis and management of such cases.
摘要：
目的：异位甲状旁腺癌（EPC）是一种罕见的临床实体，具有多种诊断缺陷，使外科手术具有挑战性。我们评估了EPC的临床病理特征和预后。
方法：在这项回顾性队列研究中，从三级转诊中心治疗的133名PC患者中确定了24名EPC。分析临床病理结果与部位的关系。
结果：EPC的位置主要是甲状腺内（62.5%），其次是纵隔的16.7%，咽后间隙为8.3％，颈动脉鞘8.3%，和4.2%在上颈部。甲状腺内EPC患者出现较高的血清钙（p=0.020），较高的血管浸润率（p=0.040），非R0初始切除的发生率（p=0.092）略高于其他异位位置。与其他PC患者相比，甲状腺内EPC患者也有更高的上呼吸道（UAT）侵袭率（p=0.070）和更高的远处转移风险（p=0.037）的趋势。甲状腺内EPC患者术后5年无病生存率略有下降，为41.5％，而其他异位部位患者为77.8％（p=0.143），其他PC患者为59.7％（log-rank=3.194；p=0.074），但没有统计学意义。
结论：与其他PC相比，甲状腺内EPC可能会引起更生化和侵入性的PC图像。在此类病例的术前诊断和处理中应特别谨慎。
方法：在这项回顾性队列研究中，从三级转诊中心治疗的133名PC患者中确定了24名EPC。分析临床病理结果与部位的关系。
结果：EPC的位置主要是甲状腺内（62.5%），其次是纵隔的16.7%，咽后间隙为8.3％，颈动脉鞘8.3%，和4.2%在上颈部。甲状腺内EPC患者出现较高的血清钙（p=0.020），较高的血管浸润率（p=0.040），非R0初始切除的发生率（p=0.092）略高于其他异位位置。与其他PC患者相比，甲状腺内EPC患者也有更高的上呼吸道（UAT）侵袭率（p=0.070）和更高的远处转移风险（p=0.037）的趋势。甲状腺内EPC患者术后5年无病生存率略有下降，为41.5％，而其他异位部位患者为77.8％（p=0.143），其他PC患者为59.7％（log-rank=3.194；p=0.074），但没有统计学意义。
结论：与其他PC相比，甲状腺内EPC可能会引起更生化和侵入性的PC图像。在此类病例的术前诊断和处理中应特别谨慎。
