Objective. The purpose of this study was to describe the clinical-pathologi
c features of what appears to be a gingival form of proliferative verrucous
leukoplakia.
Study design. Ten adult patients with recurrent and histologically progress
ive gingival leukoplakias who were diagnosed and treated at the University
of California, San Francisco between 1994 and 1999, comprised the subject g
roup for this investigation. Clinical and microscopic features were reviewe
d. Proliferation indices and p53 expression were evaluated immunohistochemi
cally and the presence of human papillomavirus (HPV) DNA was determined by
using polymerase chain reaction (PCR) amplification.
Results, Lesions presented as solitary or regional flat/papillary/verrucal
leukoplakias of the free and attached gingiva (tooth-bearing areas only). W
ith time, flat lesions developed a papillary or verruciform profile. Althou
gh lesions were recurrent, they were confined to the gingiva, and multiple
lesions did not develop. Half the patients used tobacco, and HPV could not
be detected by using PCR. Microscopically 6 cases began as hyperkeratotic l
esions, and 3 initially exhibited a psoriasiform pattern with a marked infl
ammatory component. With recurrences, the lesions became progressively atyp
ical histologically. The proliferation indices for these lesions showed mod
est increases over normal epithelium, and positive p53 staining was evident
in 4 of 10 cases, indicating a disruption of the keratinocyte cell cycle i
n these lesions. The mechanism associated with the positive p53 staining (p
rotein binding to wild type p53 versus mutation of the p53 gene) was not de
termined. Lesions recurred after conservative scalpel or laser excision, an
d many developed into verrucous or squamous cell carcinoma.
Conclusions, Proliferative verrucous leukoplakia of the gingiva (PVLC) appe
ars to be a subset of oral proliferative verrucous leukoplakia. It can be c
haracterized as a solitary, recurring, progressive white patch that develop
s a verruciform architecture and may not be associated with HPV. PVLC has a
n unpredictable course and is at risk for development into verrucous or squ
amous cell carcinoma. Currently there is no way to determine or predict whi
ch gingival white lesions will follow the clinical course described for thi
s group of patients with PVLG.