Perianal Paget's disease. Classification and review of management: report of two cases.

Fewer than 100 cases of Paget's disease located in the perianal skin have been reported since the extramammary location was first described in 1893. Two patients seen and treated in the authors' institutions with disease limited to the epidermis and its adnexae are described to illustrate the usual presentation and pathobiology of the disease. A staging classification based on the disease pathology has been developed from the cases reported in the literature and correlated with appropriate surgical treatment. Stage I disease treated with wide local excision promises unlimited survival, whereas the prognosis worsens for Stage II, with synchronous localized malignancies, and for Stages III and IV, with regional and distant metastatic disease, respectively.