Spontaneous regression of pulmonary metastases from testicular embryonal carcinoma.

A 22-year-old man was referred to our hospital for a lung tumor on a chest X-ray examination. Computed tomography of the chest revealed multiple coin lesions. Magnetic resonance imaging of the left testis showed an 8-mm tumor that was hard and palpable. Testicular tumor with lung metastasis was diagnosed and orchiectomy was performed. The histopathological diagnosis was embryonal carcinoma with infiltration of histiocytes. Four days after the operation, a chest X-ray showed a remarkable regression of the lung tumors. Chemotherapy was not performed because the metastatic lesions continued to regress spontaneously. Six months later, no tumor was observed on computed tomography images of the lungs.