A 43-year-old men presented with left supraclavicular growing mass. Ultrasonography revealed a 31 x 21 mm solid mass with a homogeneous echoic pattern. Lymph node metastasis of some malignant neoplasms was highly suspected. However, whole body evaluation with computed tomographic scan revealed no findings in the primary region. In addition, tumor markers including alpha fetoprotein, human chorionic gonadotropin and carcinoembryonic antigen were within normal limits. Then, extirpation of supraclavicular mass was performed and pathological diagnosis was made as pure seminoma. Evaluation of testicle by ultrasonography revealed a diffuse calcification. However, histological examination of biopsy specimen of testicle revealed no malignancy. The mass was finally diagnosed as extragonadal or "burned-out" pure seminoma. The patient received two courses of Peplomycin, vinblastine and cisplatin (PVP) therapy, and there has been no evidence of recurrence for 34 months.