Malignant transformation of testicular teratoma: A chemoresistant phenotype

Abstract

Purpose To review our experience in the management of malignant transformation of teratoma (MTT). Materials and methods Nine patients with MTT were identified from January 1980 to August 2005, with all pathological specimens re-reviewed by a single genitourinary pathologist. Results Two patients presented with clinical stage I disease in which malignant transformation occurred within the primary testis tumor (rhabdomyosarcoma in 1 and adenocarcinoma in 1). These patients underwent a primary retroperitoneal lymph node dissection (RPLND). No viable tumor was identified in the specimen, and both patients were alive without disease at 16 months follow-up. Of the remaining 7 patients, the clinical stages were IIA (N = 1), IIB (N = 3), and III (N = 3), and all were treated with chemotherapy followed by RPLND. The MTT histology of these RPLND specimens consisted of adenocarcinoma (N = 3), rhabdomyosarcoma (N = 2), angiosarcoma (N = 1), and astrocytoma (N = 1). Following preoperative chemotherapy, a significant radiologic response (defined as more than a 25% reduction in maximum tumor circumferential diameter) was demonstrated in 1 patient, and normalization of serum tumor markers was demonstrated in 6. At a mean follow-up of 5 years, 3 of these 7 patients were alive with no evidence of disease, 1 had persistent disease, and 3 had died of disease, and their median disease-specific survival duration was 4.6 years. Conclusions In our experience, MTT is significantly resistant to current chemotherapeutic regimens, as demonstrated by its poor radiologic response to treatment. Alternative therapeutic strategies targeted to MTT are thus needed.