Oral Carcinoma Arising Under Implant-Supported Prosthesis: Progression of Proliferative Verrucous Leukoplakia Initially Mimicking Lichen Planus
Proliferative verrucous leukoplakia (PVL) is a non-homogenous type of oral leukoplakia, characterized by multifocal white plaques, propensity to recur after treatment, with strong tendency towards malignant transformation. Interestingly, some studies show that, at initial stages, PVL may resemble oral lichen planus (OLP), potentially leading to misdiagnosis. A 52-year-old woman, with a previous OLP diagnosis, was referred to our service for implant installation and follow-up of OLP lesions. After clinicopathological re-evaluation, a diagnosis of PVL (early stage) was made, and a maxillary full-arch implant-supported prosthesis supported by implants was installed. After 6 years of follow-up, the patient developed squamous cell carcinoma around the implants. The current case emphasizes that PVL patients with oral lesions suggesting peri-implantitis or peri-implant mucositis deserve a more meticulous investigation.

Clinical features. Intraoral examination revealed multifocal and large erosive lesions on the palate, alveolar ridge (a), buccal mucosa (b), and gingiva (c). Also, white plaques on the tongue and gingiva were observed (d–f).

Clinical features after two years of follow-up of Figure 1. The patient has a full-arch implant-supported prosthesis (FAISP) supported by 6 implants on the maxilla (a and b). Moreover, a widespread growth of the lesions on the palate (b), buccal mucosa (c, d), tongue (e), and floor of the mouth (f) was noticed.

Clinical features after 2 years of follow-up of Figure 2. New thick, rough, white plaques on the upper and lower labial mucosa (a and b), palate (c), and tongue dorsum (d). The verruciform nodular lesion on the alveolar ridge was diagnosed as verrucous carcinoma (e). After 2 years of follow-up of Figure 3c, notice the upper alveolar ridge showing an extensive ulcerative lesion around the implants (b), diagnosed as squamous cell carcinoma.

Sequential histopathological features of PVL initially mimicking OLP. Mild verruciform epithelial hyperplasia associated with lichenoid infiltrate (a, corresponding to Figure 1). Hyperortokeratosis and mild epithelial dysplasia associated with lichenoid infiltrates (b, corresponding to Figure 2e). Severe epithelial dysplasia and foci of lichenoid infiltrate (c, corresponding to Figure 2f). Well-differentiated squamous cell carcinoma with infiltrative features (d, corresponding to Figure 3f) (H&E stain, original magnification ×20).
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