Treatment-Resistant Giant Unilateral Bowen’s Disease of the Scalp Responding to Radiotherapy

In 2009, a 68-year-old man with a history of significant sun exposure and no history of arsenic exposure presented with a large, treatment-resistant plaque of Bowen's disease on his hair-bearing scalp. Previous treatments, including topical 5-fluorouracil, imiquimod, cryotherapy, and curettage, were either not tolerated or ineffective. Photodynamic therapy (PDT) with methyl aminolaevulinate (MAL) was also poorly tolerated and only partially effective. The patient then received electron-beam therapy, which resulted in an excellent response in the treated areas, although some disease persisted outside the radiotherapy field. The case highlights the effectiveness of radiotherapy for treating large plaques of Bowen's disease on the scalp when other treatments have failed, particularly in areas that heal well.