Vajihinejad Maryam, Ataei Ali, Pashmchi Mohammad, Aledavoud Ali, Zand Vahid, Broomand Mohammad Ali, Mohammadi Mohammad, Reshkuiyeh Niloofar Zare
Department of Pathology, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.
School of Medicine, Bam University of Medical Sciences, Bam, Iran.
Front Oncol. 2024 May 3;14:1394020. doi: 10.3389/fonc.2024.1394020. eCollection 2024.
Intrathyroid thymic carcinoma (ITTC) is a rare neoplasm of the thyroid, which accounts for less than 0.15% of all thyroid malignancies. The coexistence of ITTC and papillary thyroid carcinoma (PTC) is an extremely rare condition reported only in a limited number of cases.
A 26-year-old female presented with a growing neck mass, hoarseness, and dysphagia over four months. Ultrasonography revealed that the entire left lobe and the isthmus of the thyroid were replaced with a hypoechoic mass. Moreover, it revealed two hypoechoic nodules in the right thyroid. The patient underwent a total thyroidectomy and paratracheal lymph node dissection. Histopathological examinations revealed the coexistence of ITTC and PTC in the same thyroid. In immunohistochemical analyses, the ITTC was positive for CD5, P63, CD117, and CK 5/6 and negative for thyroglobulin, calcitonin, and TTF 1. At the same time, PTC was positive for TTF 1 and thyroglobulin and negative for CD5, P63, and CK 5/6. The patient received postoperative radiotherapy and remained well with no evidence of recurrence during one month follow-up.
Distinguishing ITTC from other thyroid malignancies before the surgery is challenging due to its non-specific presentations. Therefore, the diagnosis relies on postoperative studies, especially immunohistochemistry. The recommended treatment approach to improve survival in ITTC cases is total thyroidectomy combined with cervical lymph node dissection, followed by postoperative radiotherapy. The coexistence of ITTC and PTC may indicate the similarity in the underlying mechanisms of these tumors. However, further investigations are needed to understand this potential correlation.
甲状腺内胸腺癌（ITTC）是一种罕见的甲状腺肿瘤，占所有甲状腺恶性肿瘤的比例不到0.15%。ITTC与甲状腺乳头状癌（PTC）共存是一种极为罕见的情况，仅在少数病例中有报道。
一名26岁女性在四个月内出现颈部肿块增大、声音嘶哑和吞咽困难。超声检查显示甲状腺的整个左叶和峡部被一个低回声肿块取代。此外，还发现右侧甲状腺有两个低回声结节。患者接受了甲状腺全切术和气管旁淋巴结清扫术。组织病理学检查显示同一甲状腺内存在ITTC和PTC共存。免疫组化分析中，ITTC对CD5、P63、CD117和CK 5/6呈阳性，对甲状腺球蛋白、降钙素和TTF 1呈阴性。同时，PTC对TTF 1和甲状腺球蛋白呈阳性，对CD5、P63和CK 5/6呈阴性。患者接受了术后放疗，在一个月的随访期间情况良好，无复发迹象。
由于ITTC的表现不具有特异性，术前将其与其他甲状腺恶性肿瘤区分开来具有挑战性。因此，诊断依赖于术后检查，尤其是免疫组化。提高ITTC病例生存率的推荐治疗方法是甲状腺全切术联合颈部淋巴结清扫术，随后进行术后放疗。ITTC和PTC的共存可能表明这些肿瘤在潜在机制上具有相似性。然而，需要进一步研究来了解这种潜在的相关性。
