Desmoplastic Nevus Versus Desmoplastic Melanoma

Among the melanocytic lesions with most difficult differential diagnosis we should include those with spindle and fibrous stroma (i.e., desmoplastic features). This is true not only because both benign and malignant melanocytic lesions may show these morphologic features (desmoplastic nevus and desmoplastic melanoma), but also since other, non-melanocytic lesions may present in the skin with similar features. Thus, scars, dermatofibromas, granulomatous dermatitis, metastatic carcinomas, etc., enter in this differential diagnosis. This chapter summarizes the morphologic and immunohistochemical features most helpful in reaching the correct diagnosis.