Dermoscopic Evaluation Improves Clinical Diagnosis of Oral Melanotic Macules: A Study in 50 Patients with Oral Pigmented Lesions

Abstract

BACKGROUND: Dermoscopy is a non-invasive in vivo method rarely used for the diagnosis of oral pigmented lesions. OBJECTIVE: To analyze clinical, dermoscopic, and histologic features of Oral Melanotic Macules (OMMs), and to evaluate the usefulness of dermoscopy in the diagnosis of OMMs. METHODS: Fifty patients presenting solitary or multiple circumscribed pigmented lesions in the oral mucosa were included. RESULTS: OMMs were diagnosed in 19 patients (84% women and 16 % men); 52 % of patients had multiple lesions, 48% had one lesion. Lesion sites in decreasing order of frequency were the labial mucosa (63 %), gingiva (31.57 %), cheek mucosa (26.31%), labial semimucosa (21%), palate (10.52 %), alveolar ridge (5.26 %) and tongue (5.26 %). The dermoscopic pattern of OMMs was linear in 89 % of cases (47% parallel line, 35% fish scale-like, and 17% hyphal patterns). Histological analysis showed increased melanin in the basal cell layer in all cases with a linear dermoscopic pattern, slight acanthosis in 14 cases, and a slight increase in number of basal melanocytes in 13 cases. Globules were seen in 21% of cases corresponding histologically with increased melanin or melanophages in the lamina propria. The dermoscopic observation of symmetrical lines further enhances the diagnostic ability of dermoscopy in OMMs, with 73.68% sensitivity, 87.1% specificity, 77.78% positive predictive value, 84.38 % negative predictive value, 5.71 positive likelihood ratio, and 0.30 negative likelihood ratio. CONCLUSIONS: Dermoscopy may play a role in improving noninvasive diagnosis of oral pigmented lesions occurring on several areas of non-keratinized mucosa.