Spontaneous apparent clinical resolution with histologic persistence of a case of extramammary Paget's disease: response to topical 5-fluorouracil.

An 86-year-old woman presented with a 3-year history of an erythematous axillary lesion, which was histologically confirmed to be extramammary Paget's disease (EMPD) confined to the epidermis and adnexa. Surprisingly, spontaneous clinical regression occurred in the lesion, but Paget's cells persisted within the epidermis and adnexa on histologic examination. One year of intermittent topical chemotherapy with 5-fluorouracil resulted in ulcers that were interpreted as EMPD and completely excised. Histologic examination showed a complete absence of Paget's cells. To our knowledge, only one previous report investigated apparent spontaneous clinical resolution with histologic persistence of EMPD. We emphasize that topical 5-fluorouracil cannot be considered a safe treatment modality for EMPD, but it may be useful in certain cases in which the extent of the lesions, or the general condition of the patient, advise against surgery or radiotherapy.