Comparison of clinical and dermoscopic features between extramammary Paget's disease and chronic eczema

Extramammary Paget's disease (EMPD) is a rare cutaneous malignancy that is easily confused with other diseases, especially chronic eczema. This study focuses on the clinical and dermoscopy characteristics of EMPD and chronic eczema, aiming to identify the key points of differentiation between the two and evaluate the role of dermoscopy in differential diagnosis. The study retrospectively analyzed 40 patients with EMPD and 40 patients with chronic eczema who were diagnosed with histopathological examination in the dermatology department of our hospital from January 2020 to December 2024. The clinical and dermoscopy characteristics of the two groups were analyzed, and differences were compared using t-tests and chi-square tests. P < 0.01 was considered statistically significant. Clinically, chronic eczema group had more common itching and significantly increased scales; while EMPD patients had a higher incidence of nodules, pigmentation, and hypopigmentation. Dermatoscopy revealed that the background color of EMPD lesions was mainly milky red, with a vascular pattern of evenly distributed punctate and globular vessels; chronic eczema was characterized by clustered punctate vessels, with statistically significant differences (P < 0.01). In addition, the EMPD group had a higher frequency of gray/brown dots, gray/brown amorphous areas, bright white lines, bright white amorphous areas, and reticular structures, with statistically significant differences (P < 0.01). This study is the first to conduct a comparative analysis on a large sample size of 80 cases. The results indicate that EMPD and chronic eczema differ in clinical and dermoscopy characteristics, and dermoscopy plays a significant role in the early and accurate diagnosis of EMPD.