Abstract：
OBJECTIVE: To determine the rate of nodal metastasis in dogs with thyroid cancer and evaluate whether immunohistochemistry (IHC) identifies additional metastases beyond evaluation with H&E.
METHODS: 70 prospectively enrolled client-owned dogs with thyroid cancer managed with thyroidectomy.
METHODS: Dogs underwent thyroidectomy with concurrent elective bilateral medial retropharyngeal (MRP) ± deep cervical lymphadenectomy. Thyroid tumors and associated lymph nodes were reviewed by a single board-certified pathologist. Immunohistochemistry was used for all primary tumors (thyroid transcription factor-1 and calcitonin) to support a diagnosis of follicular or medullary carcinoma. Lymph nodes without evidence of metastasis after H&E review were labeled with the antibody associated with the wider uptake in the primary tumor.
RESULTS: 77 thyroid cancers were resected from the 70 dogs enrolled, including 61 (79.2%) follicular, 8 (10.7%) medullary, and 7 (9.3%) mixed follicular/medullary carcinomas, with 1 (1.3%) carcinosarcoma. Twelve dogs had evidence of nodal metastasis following H&E review. Occult micrometastasis was identified in 1 dog following nodal IHC, resulting in documented metastasis in 13 of 70 (18.6%) dogs. Metastasis was more common with medullary (5/8) and follicular/medullary carcinoma (3/7) than follicular carcinoma (5/61). All MRP metastases were ipsilateral (7/77 [9.1%]), without contralateral MRP metastases (0/62). Fourteen of 41 (34.1%) deep cervical lymph nodes were metastatic.
CONCLUSIONS: Nodal metastasis was uncommon for follicular carcinoma but was seen in > 50% of dogs with thyroid cancer involving a medullary component. Routine nodal IHC appears to be low yield for thyroid carcinoma. Extirpation of ipsilateral MRP and identifiable deep cervical lymph nodes is recommended with thyroidectomy until detailed preoperative risk stratification becomes available.
METHODS: 70 prospectively enrolled client-owned dogs with thyroid cancer managed with thyroidectomy.
METHODS: Dogs underwent thyroidectomy with concurrent elective bilateral medial retropharyngeal (MRP) ± deep cervical lymphadenectomy. Thyroid tumors and associated lymph nodes were reviewed by a single board-certified pathologist. Immunohistochemistry was used for all primary tumors (thyroid transcription factor-1 and calcitonin) to support a diagnosis of follicular or medullary carcinoma. Lymph nodes without evidence of metastasis after H&E review were labeled with the antibody associated with the wider uptake in the primary tumor.
RESULTS: 77 thyroid cancers were resected from the 70 dogs enrolled, including 61 (79.2%) follicular, 8 (10.7%) medullary, and 7 (9.3%) mixed follicular/medullary carcinomas, with 1 (1.3%) carcinosarcoma. Twelve dogs had evidence of nodal metastasis following H&E review. Occult micrometastasis was identified in 1 dog following nodal IHC, resulting in documented metastasis in 13 of 70 (18.6%) dogs. Metastasis was more common with medullary (5/8) and follicular/medullary carcinoma (3/7) than follicular carcinoma (5/61). All MRP metastases were ipsilateral (7/77 [9.1%]), without contralateral MRP metastases (0/62). Fourteen of 41 (34.1%) deep cervical lymph nodes were metastatic.
CONCLUSIONS: Nodal metastasis was uncommon for follicular carcinoma but was seen in > 50% of dogs with thyroid cancer involving a medullary component. Routine nodal IHC appears to be low yield for thyroid carcinoma. Extirpation of ipsilateral MRP and identifiable deep cervical lymph nodes is recommended with thyroidectomy until detailed preoperative risk stratification becomes available.
摘要：
目的：确定甲状腺癌犬的淋巴结转移率，并评估免疫组织化学（IHC）是否发现了H＆E评估之外的其他转移。
方法：70只接受甲状腺切除术治疗的甲状腺癌患者。
方法：狗行甲状腺切除术，同时行选择性双侧咽后内侧（MRP）±颈深淋巴结清扫术。甲状腺肿瘤和相关淋巴结由一名单板认证的病理学家进行审查。免疫组织化学用于所有原发性肿瘤（甲状腺转录因子-1和降钙素），以支持诊断滤泡或髓样癌。H＆E审查后无转移迹象的淋巴结用与原发性肿瘤中更广泛摄取相关的抗体标记。
结果：从70只狗中切除了77例甲状腺癌，包括61个（79.2%）卵泡，8（10.7%）髓质，和7（9.3％）混合滤泡/髓样癌，1（1.3％）癌肉瘤。12只狗在H&E检查后有淋巴结转移的证据。1只狗在淋巴结IHC后发现隐匿性微转移，导致70只狗中的13只（18.6％）发生转移。髓样（5/8）和滤泡/髓样癌（3/7）的转移比滤泡癌（5/61）更常见。所有MRP转移均为同侧（7/77[9.1%]），无对侧MRP转移（0/62）。41个（34.1％）深颈部淋巴结中有14个转移。
结论：淋巴结转移在滤泡性癌中并不常见，但在>50％的甲状腺癌犬中可见，涉及髓样成分。常规淋巴结IHC似乎对甲状腺癌的产量较低。建议甲状腺切除术切除同侧MRP和可识别的颈深淋巴结，直到获得详细的术前风险分层为止。
方法：70只接受甲状腺切除术治疗的甲状腺癌患者。
方法：狗行甲状腺切除术，同时行选择性双侧咽后内侧（MRP）±颈深淋巴结清扫术。甲状腺肿瘤和相关淋巴结由一名单板认证的病理学家进行审查。免疫组织化学用于所有原发性肿瘤（甲状腺转录因子-1和降钙素），以支持诊断滤泡或髓样癌。H＆E审查后无转移迹象的淋巴结用与原发性肿瘤中更广泛摄取相关的抗体标记。
结果：从70只狗中切除了77例甲状腺癌，包括61个（79.2%）卵泡，8（10.7%）髓质，和7（9.3％）混合滤泡/髓样癌，1（1.3％）癌肉瘤。12只狗在H&E检查后有淋巴结转移的证据。1只狗在淋巴结IHC后发现隐匿性微转移，导致70只狗中的13只（18.6％）发生转移。髓样（5/8）和滤泡/髓样癌（3/7）的转移比滤泡癌（5/61）更常见。所有MRP转移均为同侧（7/77[9.1%]），无对侧MRP转移（0/62）。41个（34.1％）深颈部淋巴结中有14个转移。
结论：淋巴结转移在滤泡性癌中并不常见，但在>50％的甲状腺癌犬中可见，涉及髓样成分。常规淋巴结IHC似乎对甲状腺癌的产量较低。建议甲状腺切除术切除同侧MRP和可识别的颈深淋巴结，直到获得详细的术前风险分层为止。
