OBJECTIVETo investigate the clinicopathologic characteristics of primary nasopharyngeal adenoid cystic carcinoma (NPACC) and its relation to Epstein-Barr virus (EBV) infection in Guangzhou where is a high-incidence area of EBV-associated nasopharyngeal carcinoma (NPC).

METHODS17 cases of NPACC with clinical record and biopsy samples were collected in Guangzhou and their clinical manifestations were reviewed. Besides HE, Alcian blue and PAS, LSAB immunohistochemistry was performed for detecting the expression of a variety of epithelial markers, CD21 and EBV encoded LMP1. EBV encoded early RNAs (EBER) was detected by using in-situ hybridization. Nested PCR was applied for studying the presence of EBV W-fragment in tissues.

RESULTSThe ratio of male to female was 7:10. The patients' age ranged from 30 to 63 years, and the median age was 46 years. 14 out of 17 tumors showed markedly local aggressive growth, presenting as T3 or T4. However, only 1 patient had metastasis of an ipsilateral cervical lymph node. The majority of neoplastic cells were basal-cell like in shape and with scanty cytoplasm and a deeply stained nucleus. Intercellular hyaline or mucinous substance was always present in between the carcinoma cells. Cribriform structure formed by the neoplastic cells could be found in 16 out of these 17 biopsies. The NPACC always express the wide-spectrum cytokeratin and the epithelium membrane antigen. Only a few or a small number of carcinoma cells showed nuclear EBER-signals in 9 cases (9/17). Concurrently, these 9 NPACCs showed a 192 bp W-fragment positive band on electrophoresis gel by nested PCR. LMP1 expression had been found in 5 out of the 9 NPACCs (55.6%) accompanying with EBER-positive carcinoma cells. The EBER-positive infiltrating lymphocytes could also be found in the stroma of 3 out of the 9 EBER-stained NPACC slides. All the tumor cells, including the EBER-positive cell of the 17 NPACCs showed no CD21 expression.

CONCLUSIONSThe female is predominant over the male in development of NPACC, which often accompanied with a markedly invasive capacity at the nasopharynx and its neighboring sites. Only a small number of tumor cells, nearly a half of the studied cases were infected with EBV. Therefore, it's postulated that there seems no close relation present between NPACC and EBV infection.