Superficial Spreading Melanoma
The radial phase of superficial spreading melanoma (SSM) shows proliferation of atypical melanocytes arranged singly or in clusters throughout all levels of epidermis. The appearance is similar to Paget's disease. The tumor cells are epithelioid with abundant cytoplasm, pleomorphic nuclei, prominent nucleoli, frequent mitoses, and dusty melanin pigmentation. Note the prominent lymphocytic infiltrate. It is often associated with invasion, therefore such areas should be carefully examined on multiple levels.