Enlarging masses after chemotherapy for nonseminomatous germ cell tumors

Within 6 months after completing chemotherapy for nonseminomatous germ cell tumors (NSGCT), 185 men with negative serum tumor markers underwent surgical resection of residual masses. This paper presents radiologic studies which have revealed 14 men with 17 masses (10 retroperitoneal, five pulmonary, two mediastinal) that enlarged despite therapy. Thirteen of the 17 masses were teratomas; two were necrotic tissue; one was a teratoma containing NSGCT; and one was a teratoma with sarcomatous degeneration. All 12 retroperitoneal and mediastinal teratomatous masses were cystic on posttherapy CT. Although enlarging masses in these circumstances usually represent teratoma, they should be resected to provide a histologic diagnosis and to prevent potential complications