Patients and Methods: Eighty-seven patients with metastatic NSGCT underwent RPLND after having received cisplatin- or carboplatin-based induction chemotherapy. In all patients, the largest diameter of the residual mass on the transaxial plane was less than or equal to 20 mm, as assessed by abdominal computed tomography (CT) immediately before RPLND.

Results: Complete fibrosis or necrosis was found in 58 patients (67%), teratoma was found in 23 patients (26%), and vital malignant germ cell tumor was found in six patients (7%), including one patient with rhabdomyosarcoma in the RPLND specimen. In five of the six latter patients, the residual lesion was less than or equal to 10 mm at pre-RPLND CT. No pre- or postchemotherapy clinical or radiologic parameter was identified that significantly predicted the histology of the residual mass.

Conclusion: One third of retroperitoneal postchemotherapy lesions less than or equal to 20 mm contained residual vital tumor tissue, despite modern chemotherapy regimens. Therefore, postchemotherapy RPLND remains necessary in patients with minimal-size residual lesions to facilitate easy and safe follow-up and initiate additional therapy as early as possible, thus avoiding recurrences. (C) 2003 by American Society of Clinical Oncology.