Non-Melanoma Skin Cancer: Dermatoscopic Diagnostic Clues in Mexican Individuals Based on Fitzpatrick Skin Phototypes

Background/Objectives: Skin cancer is increasingly prevalent. Non-melanoma skin cancers pose a challenge, as most lesions are diagnosed at later stages and often lead to complications. Although dermatoscopy has emerged as a valuable tool that enhances the confidence of dermatologists, specific patterns for accurately identifying various subtypes of non-melanoma skin cancer have yet to be detailed. This study aimed to investigate dermatoscopic clues that facilitate accurate diagnosis of non-melanoma skin cancer among Mexican individuals. There is insufficient acknowledgment of high skin cancer rates among non-Whites. Methods: The study included fifty-three patients diagnosed with non-melanoma skin cancer, aged 39 to 89, who visited an academic dermatology department for skin examinations. Two certified dermatologists evaluated at least three dermatoscopy images for each lesion. A biopsy was taken to confirm the preliminary diagnosis. Statistical analysis was performed using GraphPad Prism v8.0, considering a probability (p) value of less than 0.05 as significant. Results: Most patients were classified as phototype III. Patients with phototype IV were younger at the time of diagnosis. Basal cell carcinomas were the most common cancer subtype. Nodular and ulcerated tumors were the most prevalent morphology. The dermatoscopic examination revealed that 60% of the lesions were pigmented, with a predominance of polymorphic vascular patterns. Squamous cell carcinomas exhibited monomorphic vascular structures. Both groups' blood vessel arrangements and specific patterns were primarily radial. Conclusions: Phototypes III and IV are predominant in the Mexican population; however, patients with non-melanoma skin cancer tend to be under 60 years of age at diagnosis. Although prominent reticular lines were distinctive of the ulcerated lesions, finding any pathognomonic pigmentary feature for non-melanoma skin cancer subtypes or locations was impossible. A polymorphic pattern of blood vessels, with a predominance of linear vessels, typically indicates the presence of Basal cell carcinoma. In contrast, a monomorphic pattern with a predominance of comma vessels is more suggestive of Squamous cell carcinoma.