Is alveolar histotype a prognostic factor in paratesticular rhabdomyosarcoma? The experience of Italian and German Soft Tissue Sarcoma Cooperative Group.

PURPOSE: To ascertain whether alveolar histology retains its adverse prognostic role in the subset of paratesticular rhabdomyosarcoma (RMS) patients, generally characterized by a very good outcome. PATIENTS AND METHODS: Twenty pediatric patients were treated over a 25-year period using the protocols of the Italian and German Soft Tissue Sarcoma Cooperative Groups. Clinical characteristics at presentation were much the same as in non-alveolar patients. RESULTS: The proportion of patients with alveolar histotype (8%) in paratesticular site was lower than in the general RMS population (20-30%). With a median follow-up of 122 months, 5-year EFS and OS were 78 and 89%, respectively. CONCLUSION: Our data suggest a distinctly better clinical behavior of paratesticular alveolar RMS than when the disease occurs at other sites. These patients were more intensively treated than the embryonal cases, however, so-although a treatment intensity reduction may be desiderable-the idea of eliminating the alkylating agents (as in low-risk embryonal paratesticular RMS) must be considered with great caution.