The growing teratoma syndrome: radiologic findings in four cases.

Radiologic findings in four patients with metastatic mixed germ-cell tumors of the testis are presented. In all cases metastases had increased in size following chemotherapy in spite of normal biomarker levels, and histological study of the residual masses showed mature teratoma with an absence of malignant cells, thus confirming the diagnosis of growing teratoma syndrome. At present CT appears to be the best technique both for diagnosis and follow-up in these patients. In one case, the growing teratoma syndrome presented as cavitation of a pulmonary nodular lesion, a finding rarely described in the literature, and with CT demonstration not reported.