Fungal Masquerader: A Case Report of Extramammary Paget's Disease Treated with Radiotherapy

An 83-year-old Caucasian male presented with a pruritic erythematous patch to his right inguinal region, which he had contracted five months ago. After months of topical antifungal and steroid therapies, the patient was referred to dermatology due to a lack of lesion improvement. A 5.0 mm punch biopsy with immunohistochemical staining revealed the presence of pleomorphic nuclei with cytoplasm replete with mucin, suggestive of superficial extramammary Paget's disease (EMPD). As he was reluctant to undergo a surgical assessment, the patient underwent consultation and management with 30 sessions of superficial electron beam radiotherapy. A week after the completion of radiation therapy, the patient's skin exhibited minimal erythema with surrounding hyperpigmentation to the affected inguinal skin, suggesting clearance of the disease. This case highlights the importance of an accurate diagnosis in a timely manner as neoplastic cases have a metastatic risk with potentially devastating results.