Our case of pigmented mammary Paget’s disease simulated melanoma clinically and dermoscopically. Histologically, the lesion was characterized by microscopic features similar to those seen in malignant melanoma and, to a lesser extent, in Bowen’s disease (intra-epidermal squamous cell carcinoma). Immunohistochemical studies demonstrated that the tumor cells were positive for keratins (Cam 5.2 + MNF 116) and AE1-AE3 and negative for HMB-45 and S-100 proteins. In conclusion clinical and dermoscopic examination cannot reliably distinguish melanoma from epithelial pre-neoplastic or neoplastic disease, therefore the differentiation of pigmented Paget’s disease from superficial spreading of melanoma and Bowen’s disease is based on histopathologic integrated with immunohistochemical criteria.
