Diagnostic and therapeutic strategies for intrathyroid thymic carcinoma

WANG Bo; WANG Si-si; HUANG Wen-yu; LIN Xuan; HE Shao-feng; ZHAO Wen-xin

doi:10.19538/j.cjps.issn1005-2208.2025.09.20

Abstract：Intrathyroid thymic carcinoma(ITTC)is an extremely rare malignant tumor arising from ectopic thymic tissue within the thyroid,with histological features resembling thymic epithelial tumors.It predominantly affects middle-aged and elderly individuals and typically presents as a painless cervical mass.Imaging lacks specificity,and ITTC is often misdiagnosed as primary thyroid squamous cell carcinoma or anaplastic carcinoma.Definitive diagnosis relies on pathology and immunophenotyping;positivity for CD5,CD1 17,and p63/p40,along with negativity for thyroglobulin(Tg)and thyroid transcription factor-1(TTF-1),provides critical diagnostic value.The Ki-67 index,combined with the extent of necrosis and mitotic activity,can be used for risk assessment.Surgical resection with RO margins remains the cornerstone of treatment,with routine central lymph node dissection recommended,while lateral neck dissection is reserved for cases with confirmed metastasis or high-risk factors.Postoperative radiotherapy may improve local control in high-risk patients.In recurrent or progressive cases,programmed death-1(PD-1)/programmed death-ligand 1(PD-L1)inhibitors have shown potential efficacy in patients with high expression,and targeted therapies are under investigation.Overall,the precise management of ITTC requires integration of morphology,immunohistochemistry,and molecular data,with individualized treatment planning formulated by a multidisciplinary team(MDT).Future multicenter prospective studies are needed to clarify the optimal indications for radiotherapy,immunotherapy,and targeted therapy,and to validate the clinical value of molecular subtyping and dynamic monitoring.