Background: Undifferentiated carcinomas of the major salivary glands are rare malignant neoplasms of the head and neck region, and patients with these lesions have a poor prognosis. Patients with lymphoepithelial carcinoma (LEC), a specific subtype of undifferentiated carcinoma, however, have a better prognosis, and LEC seems to differ from large cell undifferentiated carcinoma (LCUC) clinically.
Methods: Sixteen patients with LEC and 12 patients with LCUC were retrieved from the records of 295 patients who had malignancies of the major salivary glands. A retrospective study on clinical manifestations, treatments, long-term outcomes, and an association with Epstein-Barr virus (EBV) by EBV-encoded small RNA-1 in situ hybridization was conducted to identify their differences.
Results: The median patient age was 44.5 years in the LEC group and 56 years in the LCUC group. At the time of presentation, patients with LCUC had a history of rapid-growing tumor and more advanced locoregional disease (Stage IV in 75% of patients with LCUC compared with 13% of patients with LEC). All 16 patients with LEC underwent curative surgery and radiotherapy, and their 5-year survival rate was 85.6%. In the LCUC group, only 7 patients were eligible to undergo radical surgery and receive radiotherapy, and their 2-year survival rate was only 36%. Age > 50 years was associated with a significantly worse prognosis for patients with LCUC. Neck metastasis and tumor size > 6 cm tended to be poor prognostic factors. Tumors were positive for harboring the EBV genome in all 16 LEC samples but in none of the LCUC samples.
Conclusions: The clinicopathologic features of LEC and LCUC of the major salivary glands were different. LEC was associated with EBV, and patients with LEC had a much better prognosis compared with the prognosis for patients with LCUC. Therefore, LEC should be put in an independent group and should not be included in the same category as undifferentiated carcinomas of the salivary gland.