To investigate the clinicopathological characteristics of intrathyroid thymic carcinoma (ITTC), related to molecular mechanisms, treatment and prognosis, 4 cases of ITTC were retrospectively reviewed. The clinicopathological data, immunophenotypic characteristics, Epstein-Barr virus infection and related literatures were analyzed to improve understanding of the disease. All 4 patients were female, aged 36 to 63 years. The maximum diameters of the tumor were between 0.7 and 3.0 cm. Histologically, the tumor cells were arranged in cords, nests, or islands and lobulated with a pushing edge. Thymus corpuscular structures were observed in some areas. Immunohistochemical staining showed positive expressions of CD5, CD117, CK/pan, CK5/6, p63, p40, and Ki-67 proliferation index was 10% to 30%. The EBER test results of in situ hybridization were negative. One case was complicated with papillary thyroid carcinoma (PTC), all cases underwent thyroidectomy and local lymph node dissection. After 10 to 34 months of postoperative follow-up, all cases had no recurrence or metastasis. ITTC is a rare thyroid tumor with good prognosis. It is difficult to diagnose with intraoperative freezing and fine needle puncture, especially combined with other thyroid tumors. Combined with immunohistochemistry, it is helpful for diagnosis and differential diagnosis.