Malignant Leydig cell tumor of the testis associated with Klinefelter's syndrome

We reported the case of a 35-year old man with Klinefelter's syndrome and a malignant Leydig cell tumor of the testis. Bilateral gynecomastia and righ t testicular enlargement led the patient to seek medical assistance. Despit e initial orchidectomy two years later the patient developed lung and iliac lymph node metastases. The tumor appeared to be refractory to chemotherapy and to hormonal treatments including op'DDD. Finally, the patient died wit hin 20 months of developing metastases. Leydig cell tumor is an exceedingly rare tumor, especially when associated with Klinefelter's syndrome. This a ssociation as well as presentation, pathologic features, hormonal abnormali ties, clinical course and response to therapy of malignant Leydig cell tumo rs are discussed.