Abstract: Nodular melanoma is the aggressive subtype of melanoma, with rapid growth rate and metastatic potential, which accounts for 10%-15% of all melanomas. The tumor may be nodular or polypoid (polypoid melanoma). The patient was a 30-year-old female with a dark red nodule on the extension side of the left upper arm for more than 5 years, which became worse for 1 year. Histopathologic examination showed a large number of diffuse infiltration of tumor cells in the dermis, with large and abnormal nuclei, and a large number of mitotic figures. Immunohistochemistry showed MelanA, SOX-10, Ki-67, P53, S-100 are positive, at IV grade of Clark classification. The diagnosis of nodular malignant melanoma was made.

Key words: malignant melanoma, nodular malignant melanoma