HISTOPATHOLOGIC PATTERNS OF NASOPHARYNGEAL MALIGNANCY IN LAGOS UNIVERSITY TEACHING HOSPITAL (LUTH) AND ITS ASSOCIATION WITH EPSTEIN-BARR VIRUS (EBV); A 10 YEAR RETROSPECTIVE STUDY (JANUARY 2003 TO DECEMBER 2012)

Abstract

BACKGROUND
Nasopharyngeal cancer (NPC) is a rare cancer worldwide. It is now found to be increasing in
incidence in Nigeria, though the incidence is lower when compared to countries in the Mediterranean
basin, North Africa and Southeast Asia. NPC is frequently associated with Epstein-Barr virus (EBV),
but no previous study was done in this centre to document the association
OBJECTIVES
To determine the prevalence, histologic types and age distribution of nasopharyngeal malignancy in
Lagos University Teaching Hospital (LUTH) and its association with Epstein-Barr virus (EBVld)
over a period of 10 years, between January 2003 to December 2012
MATERIALS AND METHODS
The materials for this study consisted of paraffin embedded tissue blocks, hospital request forms,
patients case notes and duplicate copies of histopathology reports of cases of histologically-diagnosed
nasopharyngeal cancer at Anatomic and Molecular Pathology Department of Lagos University
Teaching Hospital (LUTH) between January 2003 and December 2012.
The cancer was reclassified into epithelial and non-epithelial malignancy. Under the epithelial
malignancy, is the nasopharyngeal carcinoma which is reclassified in accordance with World Health
Organisation (WHO) classification.
Immunohistochemistry (IHC) for EBV latent membrane protein-1 (LMP-1) were also done to
evaluate the prevalence of Ebv in nasopharyngeal malignancy.
RESULTS
A total of seventy five (75) histologically-confirmed cases of nasopharyngeal malignancy were seen
during the study period, which constituted 1.1% of the total cancer recorded at the Anatomic and
ix

Molecular Pathology Department of LUTH. There were 47 males (63%) and 28 females (37%) with a
male to female ratio of 1.7:1. The age ranged from 3 to 75 years with the overall mean age of
44.1years.The peak age of incidence was 40 -49 years for males and 50 – 59 years for females.
The commonest presenting complaint was cervical lymphadenopathy thirty (36.2%), followed by
nasal blockage (22.3%) and epistaxis (16.0%) while the least common presentation was cranial nerve
palsy (1.1%). Other symptoms seen were hearing impairment 6.4%, proptosis 5.3%, nasal discharge
4.3%, visual impairment 4.3%, ear pain 2.1% and weight loss 2.1%.
On histological classification, undifferentiated carcinoma (WHO type III) was the commonest
(49.3%), differentiated non-keratinizing squamous cell carcinoma (WHO type II) and keratinizing
squamous cell carcinoma (WHO type I)accounted for 24% and 9.3% respectively, thus
nasopharyngeal carcinoma accounted for 82.6% of the total cases of nasopharyngeal malignancy
seen. Other histological types seen were non-Hodgkin lymphoma 13.3%, well differentiated
adenocarcinoma 2.7% and low grade mucoepidermoid carcinoma 1.3%.
EBV LMP-1 IHC was positive in thirty (86%) out of the thirty five cases studied and these consisted
of all the 14 cases of undifferentiated carcinoma, 5 cases of non-Hodgkin lymphoma and 2 cases of
adenocarcinoma. Also seven out of eleven cases of differentiated non-keratinizing squamous cell
carcinoma (WHO type II) were EBV positive and two of the three cases of keratinizing squamous cell
carcinoma (WHO type 1) were EBV positive.
CONCLUSION
This study has shown that nasopharyngeal malignancy is not uncommon in Lagos University
Teaching Hospital (LUTH). Undifferentiated carcinoma (WHO type III) was the commonest
nasopharyngeal malignancy reported from this study. The cancer occurred more frequently in males
than in females with the peak age of incidence at 5th decade of life and it is highly associated with
EBV.