Fontana–Masson Staining in Aneurysmal and Hemosiderotic Dermatofibromas: A Study of 79 Cases

This study demonstrates that HDF/ADF stain with Fontana-Masson suggests the presence of melanin in these dermatofibroma subtypes, although Fontana-Masson is not entirely specific for melanin. These findings indicate that ADF/HDF are often highlighted by Fontana-Masson, suggesting that Fontana-Masson may not be a reliable tool for distinguishing HDF/ADF from melanocytic lesions. SOX-10/S100 may be useful in differentiating HDF/ADF from melanocytic lesions.