Clinicopathological Correlation and Recurrence Outcome of Adnexal Involvement on Primary Extramammary Paget's Disease (EMPD).

Introduction Primary extramammary Paget's disease (EMPD) is a rare neoplasm that manifests as well-defined erythematous plaques, often misdiagnosed due to its similarity with different dermatoses. It may exhibit invasive features, involving adnexal invasions. The study aims to assess and compare the clinicopathological correlation of primary EMPD with adnexal features. Materials and methodology The monocentric observational retrospective study observed 43 confirmed primary EMPD cases in patients aged 45-95, excluding those with infectious dermatoses, pseudo-tumors, secondary lesions, or survived less than a month. Demographical, clinical and pathological observations were recorded. Expert dermatopathologists, blinded to the initial diagnosis, conducted a comprehensive histopathological evaluation yielding differential pathological diagnosis. Statistical analysis involved Pearson's Chi-square, Mann-Whitney U, and Spearman's Correlations for clinicopathological concordance and adnexal features. Recurrence was evaluated using Kaplan-Meier and log-rank tests, while multivariate recurrence analyses include Cox regression. A p-value < 0.05 was deemed significant. Results There was a significant association between adnexal involvement and the site of lesion (p < 0.05). There was a significant association (p < 0.05) between involved adnexal depth and primary EMPD subtypes. Adnexal involvement has a significant association with the concordance rates derived from clinicopathological correlations (p < 0.05). Smaller lesions and non-invasive EMPD significantly predict longer recurrence onset (p < 0.01). The primary EMPD subtype was the only independent predictor for recurrence time using the Cox regression model. Conclusion Adnexal proliferation in primary EMPD is considered vital on clinicopathological correlations and recurrence predictions, suggestive of its utility on both diagnosis and prognosis.