Table 1_Thyroid and breast carcinomas in a patient with Pendred syndrome: a case report and literature review.docx

BackgroundGoiter in the course of Pendred syndrome may in rare cases be associated with thyroid cancer (about 1% of all Pendred syndrome patients). The coexistence of Pendred syndrome with both thyroid and breast cancer is an even rarer condition reported in only one case.
Case presentationWe report a case of a patient diagnosed with Pendred syndrome, who concurrently developed follicular thyroid cancer and breast cancer. After receiving four cycles of neoadjuvant THP (trastuzumab + pertuzumab + docetaxel) chemotherapy, the patient underwent left mastectomy and bilateral thyroidectomy. Postoperative pathology confirmed follicular thyroid carcinoma, while no residual malignancy was detected in the breast tissue. Genetic analysis of the SLC26A4 gene revealed mutations in intron 7 (c.919.2A>G) and exon 3 (c.170C>A) on chromosome 7. To minimize the risk of axillary metastasis, the patient received postoperative breast radiotherapy. At over one year of follow-up, there were no signs of recurrence for either cancer.
ConclusionsThe coexistence of Pendred syndrome with both thyroid and breast carcinoma is extremely rare, and the underlying mechanisms remain uncertain. Current evidence does not support SLC26A4 as a driver oncogene, and the concurrence of malignancies may represent a coincidental finding rather than a causal association. Nonetheless, comprehensive genetic testing should be considered for patients with Pendred syndrome, and family-based screening is recommended once pathogenic SLC26A4 variants are identified. Long-term surveillance of the thyroid and breast is essential for early detection and timely management of potential malignancies in these patients.

背景 彭德莱综合征（Pendred syndrome）患者病程中伴发的甲状腺肿，极少数情况下可合并甲状腺癌（约占所有彭德莱综合征患者的1%）。而彭德莱综合征同时合并甲状腺癌与乳腺癌的情况更为罕见，目前仅见1例报道。
病例报告 本文报告1例确诊为彭德莱综合征的患者，同时罹患滤泡状甲状腺癌与乳腺癌。患者接受4周期新辅助THP（曲妥珠单抗+帕妥珠单抗+多西他赛，trastuzumab + pertuzumab + docetaxel）化疗后，行左侧乳腺切除术与双侧甲状腺切除术。术后病理证实为滤泡状甲状腺癌，乳腺组织未检测到残留恶性病变。对SLC26A4基因进行遗传学分析，发现7号染色体上内含子7（c.919.2A>G）与外显子3（c.170C>A）存在突变。为降低腋窝淋巴结转移风险，患者术后接受了乳腺放射治疗。随访时长超1年，两种癌症均未出现复发征象。
结论 彭德莱综合征同时合并甲状腺癌与乳腺癌的情况极为罕见，其潜在发病机制尚未明确。目前尚无证据支持SLC26A4基因为驱动致癌基因，两种恶性肿瘤的并发或属偶然发现，而非因果关联。尽管如此，对于彭德莱综合征患者仍应考虑开展全面基因检测，若检出致病性SLC26A4变异，则推荐进行家系筛查。长期监测甲状腺与乳腺状况，对该类患者潜在恶性肿瘤的早期发现与及时处置至关重要。