Proliferative verrucous leukoplakia. Four cases with flow cytometric analysis.

Proliferative verrucous leukoplakia is a slow-growing but highly aggressive precancerous form of leukoplakia of unknown cause. Proliferative verrucous leukoplakia is though to possess a continuous spectrum of clinical and histopathologic expression, ranging from simple hyperkeratosis to invasive squamous cell carcinoma. Early diagnosis is difficult because of an initial innocuous character, but multiple and rapid multifocal warty recurrences are common. This article reports four additional archival cases of proliferative verrucous leukoplakia to determine if flow cytometric analysis can be useful in the early diagnosis of proliferative verrucous leukoplakia. Flow cytometric analysis was performed on available formalin-fixed paraffin-embedded specimens (N = 27). Flow cytometric analysis results showed DNA aneuploid cell lines in each proliferative verrucous leukoplakia case studied (DNA index range, 1.1 to 2.6). In all four patients the abnormal cell line DNA index appeared to be maintained throughout the sampling period. The results suggest flow cytometric analysis could be a possible aid in early recognition of proliferative verrucous leukoplakia and might enable aggressive therapy at an earlier stage.