Objective · To investigate the clinicopathological features of intrathyroid thymic carcinoma. Methods · Clinical data of 5 patients with intrathyroid thymic carcinoma were retrospectively reviewed. Histological examination and immunohistochemical staining were performed on the surgically resected tumors. The infection of EB virus (EBV) was detectedin situ hybridization of EBV-encoded RNAs (EBER). BRAF V600E mutation was examinedamplification refractory mutation system. Results · There were 3 males and 2 females with age between 51 and 69 years (average of 60.8 years). All 5 cases were intrathyroid tumors. The tumors were 2.0-3.5 cm in diameter. All 5 cases showed positive staining for CK, CK19, P40, CD5, CD117, Bcl-2, and Ki-67 at protein level, and negative staining for other related differential diagnosis markers including 34βE12, TPO, TG, TTF1, SYN, EBV, and BRAF. In situ hybridization of EBER showed negative results and no BRAF V600E mutation was found. Conclusion · Intrathyroid thymic carcinoma is a low-grade malignant tumor. Expressions of CD5 and CD117 in tumor cells play a very important role in the differential diagnosis.