Abstract

A sixty-year-old male with pagetoid Bowen's disease is reported. A reddish-brown plaque of 35×40mm was noticed on his left lower leg about 3 years previously. Brown or black thick scales were present at the center of the plaque. Light microscopy of the biopsy lesion taken from the plaque by a practicing doctor revealed large pagetoid cells within the hypertrophic epidermis. The atypical and clear pagetoid cells suggested the diagnosis of extramammary Paget's disease, pagetoid melanoma or pagetoid Bowen's disease.
Immunohistochemical studies; the pagetoid cells were positively stained with keratin but negatively stained with S-100 protein, or carcinoembryonic antigen. We therefore, diagnosed the lesion as pagetoid Bowen's disease. When examined the excised specimen, the center of the lesion showed the features of typical Bowen's disease. However, pagetoid cells were present at the margin of the lesion. Electron microscopically, aggregated tonofilaments were observed around the nuclei of the pagetoid cells: the cells showed the feature of atypical keratinization.