Spitzoid melanocytic lesions may be broadly categorized into Spitz nevi, Atypical Spitz tumor(AST)s, and spitzoid melanomas. Atypical Spitz nevus have overlapping features of both Spitz nevi and Spitzoid melanoma, and consequently, generate controversies with diagnosis and management. A 19-year-old male patient presented with dome-shaped, erythematous nodule on the posterior side of right thigh. The lesion was first recognized a month ago and there was no accompanying symptoms. On physical examination, the papule was 6mm in diameter with symmetric, and no ulcer. Laboratory tests were not performed, and family history was unspecified. Histologically, the lesion shows well circumscribed tumor nest from the dermo-epidermal junction to the reticular dermis with a few epidermal pagetoid spread. The nest composed of large epithelioid cells with prominent nucleoli. Each cells showed uniform pleomorphism and some had mitosis. Kamino bodies were observed, and closer inspection revealed incomplete maturation of nest in the deeper portion. Immunohistochemical study revealed positive of HMB-45, Ki index of 10-20 %, and sentinel lymph node biopsy was negative. The diagnosis of atypical Spitz tumor with lower risk of metastasis was made because of but not enough to consider a diagnosis of melanoma. The tumor was removed by total excisions. No recurrences or metastases were detected during the follow-up period of 6 months.