INTRODUCTION
Inverted papilloma (IP) is a benign epithelial tumour composes of
well-differentiated columnar or ciliated respiratory epithelium having
variable squamous differentiation. The incidence of IP approximately 0.2
to 0.6 per 100,000 population per year.1 They most
commonly arise from the lateral nasal wall (90%) with frequent
extension into the maxillary, anterior, and posterior ethmoid
sinuses.2 They are typically unilateral (95%). There
are three main clinical characteristics that attribute the tumours which
have a tendency to recur (16-60%), their destructive capacity to
surrounding structures and their propensity to be associated with
malignancy (5-13%).3 IP occurs predominantly in male
patients, with a male to female ratio of 3:1. The age range of
presentations extends from the second to the seventh decade of life. The
mean age at the time of clinical presentation is nearly 50
years.4
HPV is a small double stranded DNA virus which is approximately 8Kbp in
size. They are associated with specific mucosal and epithelial lesions
ranging from benign proliferative lesions to invasive carcinomas.
Approximately 120 genetically distinct types of human papillomaviruses
have been identified, and the genomes of more than 80 have been
completely sequenced.5 Benign lesions are usually
associated with low risk types of HPV which are the Type 6 and
11.6 HPV types 16 and 18 are classified as the
high-risk types and are commonly associated with malignant lesions. All
the identified types of HPV have appeared to be only epitheliotropic and
infect the mucosal or cutaneous epithelium of the anogenital tract or
upper respiratory tract.7. PCR-based detection of HPV
E6 oncogene expression in frozen tissue samples is generally regarded as
the gold standard for establishing the presence of
HPV.8
The recurrence and malignant transformation of nasal inverted papillomas
were related to HPV infection.9 The presence of this
virus may play a role in the biological behaviour of these epithelial
proliferations. In a meta-analysis of 1041 sinonasal papilloma analysed
for HPV, 347 (33.3%) cases were positive.10 However,
the association between HPV infection and IP is still not universally
acceptable due to the high disparate rates of HPV detection of between
0–79%.2 Due to this great variance, it was our aim
to determine the prevalence of HPV in sinonasal inverted papilloma, to
correlate the HPV genotypes with recurrence of disease and to correlate
the HPV genotypes with malignant transformation.