Abstract
A 73-year-old Japanese woman was referred to our hospital because of a left leg skin tumor which was gradually growing. Clinical examination revealed a 14 × 13mm brownish keratotic plaque on her leg. Since an excisional biopsy specimen taken by a local dermatologist suggested squamous cell carcinoma, we performed an excisional biopsy. Histologically, the lesion consisted of proliferating keratinocytes. The periphery of the tumor showed reticulated seborrheic keratosis ; whereas in the center portion of the tumor, tumor cells consisted of atypical keratinocytes in the entire epidermis which was considered to be Bowen's disease. We should keep in mind that although rare, skin cancer, including Bowen's disease, could arise in a lesion of seborrheic keratosis.[Skin Cancer (Japan) 2013 ; 28 : 181-184]
