부산대학교 도서관

A 96-year-old female presented with an erythema on the right lower limb from about 3 years before. She was referred to our department because the erythema did not resolve despite taking topical steroids. On the rst examination, the patient presented with 55×38 mm, oval, welldemarcated erythema with thin scales on her right lower limb. Dermoscopy revealed dotted vessels, glomerular vessels, and thin scales in milky white and milky pink background. Histopathologically, large, bright pagetoid cells with subcircular nuclei in the epidermis were observed and parakeratosis and dyskeratotic cells were partially seen. To differentiate from extramammary Paget’s disease and intraepithelial malignant melanoma, histochemical staining and immunohistochemical staining were performed. Tumor cells showed PAS (＋) (diastase-labile),AE1/AE3 (＋), CK5/6 (＋), and p63 (＋). Alcian blue staining, CK7, GCDFP-15, S-100, and CEA were all negative. Based on these results, we diagnosed the present case as pagetoid Bowen’s disease. Since the patient did not accept tumor resection and was very elderly, we administered imiquimod cream. Topical application of imiquimod lightened the erythema and it showed a tendency to disappear. A second skin biopsy was performed, and histopathological evaluation revealed that the number of pagetoid cells in the epidermis had decreased, and marked lymphocytic inltration was observed in the epidermis and dermis. Among the inltrating lymphocytes, there was a marked increase in CD8-positive cells. Based on the time-course changes in CD8-positive cells before and after application of imiquimod, our ndings suggest that imiquimod had an antitumor effect to Pagetoid Bowen’s disease by activating CD8-positive cells. Skin Research, 22 : 145-151, 2023