Extramammary Paget's disease (EMPD) ordinarily progresses slowly as adenocarcinoma in situ. However, once metastasis occurs, the prognosis is very poor. Here we report an autopsy case that died of the disease. In addition to 3 autopsy cases, we describe the typical patterns of metastasis and progression. Although EMPD can occur as both hematogenous and lymphogenous metastases, the latter form predominates in these cases. Despite advanced tumor invasion, we are often unable to recognize the tumor itself with several examinations, but only the matter due to invasions such as hydronephrosis and lymphangitis carcinomatosa. These findings are important in determining the characteristics of EMPD and managing patients with advanced EMPD. [Skin Cancer (Japan) 2006; 21: 199-205]