Non-Surgical Management of Scrotal Extramammary Paget Disease: A Case Report of a Cutaneous Malignancy Treated with Depth-Guided Superficial Radiation Therapy

Background and Clinical Significance: Extramammary Paget disease (EMPD) is a rare cutaneous adenocarcinoma that frequently involves apocrine-rich regions and may extend beyond clinically apparent margins through adnexal structures. Surgical excision remains the standard of care; however, management can be challenging in elderly patients and in anatomically sensitive areas such as the scrotum, where morbidity and functional impairment are significant concerns. Despite increasing use of radiation-based therapies, optimal superficial radiation therapy (SRT) parameters, particularly with respect to depth of penetration, remain poorly standardized. Case Presentation: An 88-year-old male with a history of melanoma, non-melanoma skin cancer, and remote prostate cancer presented with biopsy-proven EMPD involving the scrotum and perineum. Imaging demonstrated no evidence of underlying or metastatic malignancy. Given lesion size (9 × 4 cm), anatomic location, and patient preference to avoid surgery, SRT was selected. The patient underwent treatment with 70 kV energy, delivering a total dose of 5440 cGy in 17 fractions (320 cGy per fraction) administered twice weekly. Energy selection was guided by the known propensity of EMPD for adnexal extension, with the aim of improving treatment coverage of potential subclinical disease. Conclusions: This case highlights the importance of incorporating tumor depth and adnexal involvement into treatment planning for EMPD. Depth-guided SRT may represent a viable non-surgical management strategy in carefully selected patients, particularly when surgical morbidity is a concern. These findings support a more individualized, mechanism-based approach to optimizing radiation therapy in cutaneous malignancies.