Nasopharyngeal intraepithelial lesion: latent Epstein-Barr virus infection with malignant potential.
OBJECTIVE
To study the morphology and immunohistochemical expression of nasopharyngeal intraepithelial lesions and to understand their place in nasopharyngeal carcinogenesis.


RESULTS
Nine cases of nasopharyngeal intraepithelial lesion (NPIL) were diagnosed during nasopharyngeal biopsy screening for nasopharyngeal carcinoma (NPC). Two cases were associated with early invasion. All cases demonstrated specific histological features and consistent positivity on in-situ hybridization for Epstein-Barr virus (EBV)-encoded RNA. Pure NPIL lesions showed low-grade morphology while lesions associated with early invasion were high grade. Immunohistochemical studies showed increased expression of bcl-2 and essentially negative findings for BZLF1 and LMP1. High-grade lesions had relatively stronger expression of bcl-2 and p53.


CONCLUSIONS
NPIL harbours latent EBV infection and has malignant potential. Multiple steps are involved in its occurrence and progression. Low-grade and high-grade lesions should be managed differently.
Cheung
F M F
FM
Department of Clinical Pathology, Pamela Youde Nethersole Eastern Hospital, Hong Kong, China. fc@clementpang.com
Pang
S W
SW
Yau
T K
TK
Chow
S K
SK
Lo
K W
KW
D000328:Adult; D002277:Carcinoma / Q000737:chemistry / Q000473:pathology* / Q000821:virology; D002278:Carcinoma in Situ / Q000737:chemistry / Q000473:pathology* / Q000821:virology; D020031:Epstein-Barr Virus Infections / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D005260:Female; D004854:Herpesvirus 4, Human / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000821:virology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D012334:RNA, Neoplasm / Q000032:analysis; D016601:RNA-Binding Proteins / Q000032:analysis; D012269:Ribosomal Proteins / Q000032:analysis
D019253:Proto-Oncogene Proteins c-bcl-2; D012334:RNA, Neoplasm; D016601:RNA-Binding Proteins; D012269:Ribosomal Proteins; C067169:RPL22 protein, human