Primary Extramammary Paget's Disease in a Male Patient Exhibiting Genital Involvement Mimicking Clinical and Histopathological Features of Bowen's Disease: A Case Report.

Extramammary Paget's disease (EMPD) is a rare cutaneous neoplasm characterized by the proliferation of malignant glandular-origin cells within the epidermis, occurring in areas other than the mammary areola. It is more prevalent in women (65%) than men (14%). Diagnosis can be confused with other neoplastic, inflammatory, or infectious conditions, often leading to initial inappropriate treatment with antifungals or topical steroids. Bowen's disease, an in situ squamous cell carcinoma, can mimic EMPD both clinically and histologically. However, their diagnostic and therapeutic approaches differ. We present the case of a male patient with a dermatosis in the genital area affecting the pubis, base of the penis, and scrotum, manifesting as an erythematous scaly plaque with poorly defined edges. The lesion had been previously treated as an inflammatory dermatosis. Initially, the condition was diagnosed as Bowen's disease through punch biopsy, but a definitive diagnosis of EMPD was established via excisional biopsy and immunohistochemistry. The case was resolved through surgical interventions and imaging studies to rule out involvement in other areas. This report highlights the complexity of diagnosing EMPD, emphasizing the importance of a proper diagnostic and therapeutic approach supported by specialized tools and multidisciplinary management.