Extramammary Paget's disease (EMPD) is a distinct form of malignant skin neoplasm. The clinicopathological significance of cutaneous adnexal involvement in EMPD has not been investigated in detail. Surgical specimens were obtained from 53 patients with primary EMPD. Tumor involvement of cutaneous adnexal structures was evaluated using histological parameters. The degree of involvement was scored on a scale of 0-2: 0, no involvement; 1, involvement of the upper portion of the adnexa; 2, involvement of the lower portion of the adnexa. A score of 2 was regarded as significant. The presence of comedo necrosis was also examined. Adnexal involvement was identified in 46 cases (86.8%). Comedo necrosis was observed in 6 cases (11.3%). The proportions of each parameter in in situ cases were as follows: significant adnexal involvement (score 2) in 15/26 (57.7%), and comedo necrosis in 3/26 (11.5%). The corresponding proportions in cases with invasion were 21/27 (77.8%) and 3/27 (11.1%), respectively. No significant differences in adnexal involvement and comedo necrosis were detected between in situ EMPD and invasive EMPD (p>0.05). The current study suggests that the degree of adnexal involvement and the presence of comedo necrosis are not associated with tumor progression in EMPD.