婴儿和儿童的睾丸肿瘤很少见,精原细胞瘤更为罕见。本文报告一例精原细胞瘤。患儿6个月行左侧腹股沟疝修补术时,发现左侧睾丸未降。12岁时左腹股沟被踢以后,在该区发现一肿块,行左睾丸切除术,病理诊断为单纯精原细胞瘤。对三份外周血培养进行了细胞遗传学分析,结果每份培养均有约10％的细胞染色体组成为45,X。或C显带未发现45,XO的细胞中有Y型异染色质。 Testicular tumors in infants and children are rare, and seminoma is rarer. This article reports one case of seminomas. When the child had a left inguinal hernia repair at 6 months, the left testis was found to have not fallen. When the left groin was kicked at the age of 12 years, a mass was found in the area and left orchiectomy was performed. The pathological diagnosis was pure seminoma. Cytogenetic analysis of three peripheral blood cultures revealed that approximately 10% of the cells had a chromosome composition of 45,X per culture. C-banding was not found at 45, and X-type heterochromatin was present in cells of XO.