Extramammary Paget’s disease is recognized as an apocrine-origin cutaneous tumor and is localized in the intraepithelial skin lesion. However, its advanced form is intractable, and there is currently no therapeutic option with a satisfactory level of clinical outcome. Therefore, it is of great importance to identify a potential biomarker to estimate tumor advancement in extramammary Paget’s disease. Dermcidin is an antimicrobial peptide derived from the eccrine gland and is identified as a biomarker in various malignancies. To investigate the potential of dermcidin in extramammary Paget’s disease, we investigated dermcidin expression in tumors using the immunostaining technique. Although previous studies have reported that extramammary Paget’s disease has no positive staining against dermcidin, 14 out of 60 patients showed positive staining of dermcidin in our study. To clarify the characteristics of positive dermcidin in extramammary Paget’s disease, we investigated the clinical characteristics of positive dermcidin extramammary Paget’s disease patients. Positive dermcidin patients showed a significantly high frequency of lymph node metastasis. We next investigated the impact of positive dermcidin on overall survival. Univariate analysis identified that positive dermcidin showed a significantly increased hazard ratio in overall survival, suggesting that dermcidin might be a prognostic factor for extramammary Paget’s disease.