Successful photodynamic therapy of vulval Paget's disease using a novel patch‐based delivery system containing 5‐aminolevulinic acid

Case report A 66 year old Caucasian female attended for treatment of vulval Paget’s disease. She had an eight year history of persistent vulval itch, which had been treated unsuccessfully with antifungal, antibiotic and steroid creams. Biopsy at a district hospital revealed groups of large cells with atypical nuclei located within the epidermis with abundant clear to eosinophilic cytoplasm (Fig. 1A). These cells were positive with cytokeratin 7 and negative with cytokeratin 20. A diagnosis of Paget’s disease was made. There was no evidence of dermal invasion by tumour. Mammography, colonoscopy and computed tomography of the abdomen were all negative. Clinical examination showed a 4 3 cm, purple-red, well-demarcated, moist lesion on the left labia majora. Itch was graded on the visual analogue scale (0 to 10) at 8, becoming worse during the night and interrupting her sleep pattern. The patient was reluctant to undergo surgical excision and an experimental treatment using 5-aminolevulinic acid (ALA)-based photodynamic therapy was offered. Informed consent, as part of a trial protocol, was obtained. The treatment comprised part of an ongoing trial using photodynamic therapy for the treatment of a range of vulval lesions. The trial was performed under local Ethical Committee approval. A bioadhesive patch, which was developed in the School of Pharmacy, Queen’s University Belfast, containing 38 mg cm 2 ALA (Crawford Pharmaceuticals, Milton