Incomplete efficacy of 5-aminolevulinic acid (5 ALA) photodynamic therapy in the treatment of widespread extramammary Paget's disease

Photodynamic therapy (PDT) using 5-aminolevulinic acid (5-ALA) is an effective treatment for several conditions such as Bowen's disease, subsets of basal cell carcinomas and actinic keratosis. Surgical resection is the first-choice therapy for extramammary Paget's disease (EMPD), but extensive resection is highly invasive and recurrences are frequent. We report two cases of genital EMPD treated by PDT with partial efficacy. The first patient, a 78-year-old male, suffered from pubic and scrotal Paget's disease for 6 years despite numerous treatments. The second patient, a 78-year-old female, had vulvar involvement for 2 years that was resistant to multiple treatments. The disease was recurrent and chronic with important pruritus and significant impact on the quality of life. Methyl 5-aminolevulinate was applied for 3 h, and irradiation was applied with red light (630 nm) using a total light dose of 37 J/cm(2) for a period of 10 min. The patients were treated every 2 to 4 weeks for a total of at least three treatments. Both patients experienced a partial transient reduction in their symptoms. One patient had a partial transient remission (< 50% reduction of the involved surface), whereas in the other patient, PDT failed to reduce the surface area of the lesions.