Malignant transformation of testicular teratoma: A chemoresistant phenotype

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.