Epstein-Barr virus infected lymphoepithelial carcinomas of the salivary gland in the Russia-Asia area: a clinicopathologic study of 160 cases

In order to determine the prevalence of the Epstein-Barr virus (EBV) infection in salivary gland lymphoepithelial carcinomas (LEC), we have collected 160 cases from Asian countries and Russia. All the cases examined by PCR for EBV DNA BamHI fragment and in-situ hybridization for EBER-1, EBV encoded small RNA, showed positivity for EBV infection in LEC cells, while no positive signals were found in any other salivary neoplasm examined. The incidence of LEC was highest in Guanzhou, followed by Shanghai and Chengdu and lowest in the northern parts of China, Seoul, Niigata, and Moscow. The mean age of the patients with LEC was 43.9 years with no sex predilection. The Chinese patients were of the Han race, only including minor races. There were ninety-five cases found with LEC in the parotid gland (75%), 20 in the submandibular gland (5%), and 28 in the minor salivary gland (20%). Histologically, the LECs were classified into two types: small nest type and large nest type. The latter type consisted of large-sized tumor cell nests and dense lymphocytic stromata and more frequently occurred in the minor salivary gland. The former consisted of small-sized tumor cell nests with fibrous and lymphocyte-depleted stromata, which were more frequently found in the parotid gland. The results indicated that EBV infection and certain geographic factors play important roles in the pathogenesis of the salivary LEC.