Second primary tumors in proliferative verrucous leukoplakia: a series of 33 cases.

Objectives: To describe the number of second primary malignancies in a series of 33 patients with proliferative verrucous leukoplakia (PVL), detailing the mean time between primary malignancies and their clinical characteristics.
Materials and Methods: Two groups of patients were included in this study: group 1 comprised 33 PVL patients who had developed ≥ 2 oral squamous cell carcinoma (OSCC) and group 2 comprised 48 PVL patients without malignant degeneration. We compared the groups with regard to age, gender, oral location, and number of oral sites affected. For patients in group 1, we determined the locations, clinical forms, and TNM stages of oral cancers. We also recorded the intervals of time between instances of oral cancer for all patients.
Results: The groups did not differ significantly in age; however, group 1 included more women (p < 0.05). The follow-up period and number of oral PVL locations were greater in group 1 (p < 0.01). Moreover, in group 1, as the number of OSCCs increased, the intervals between them became shorter. The gingiva was the most common site. The mean number of cancers in group 1 was 3.15; five second primary tumors were diagnosed in one patient.
Conclusions: Multiple cancers in PVL patients were more frequently located on the gingiva in the form of erythroleukoplastic areas. In addition, the interval between new cancers decreased over time.
Clinical Relevance: This is the series with the highest number of cases described with second primary tumors in PVL.