Polymorphic reticulosis has recently been characterized as an angiocentric lymphoproliferative disorder of the peripheral T-lymphocytes. However, its treatment is still a matter of controversy. In order to study efficacy and toxicity of the primary treatment, we reviewed clinical features and therapeutic results in 29 patients seen at the Instituto Nacional de Cancerologia de Mexico. Nineteen patients received primary local irradiation and 10 patients primary combination chemotherapy. In the radiotherapy group, 14 (74%) patients achieved complete response, but only 4 (40%) did so in the primary chemotherapy group. Five patients in the latter group died of treatment-related complications. The 5-year actuarial survival rate was 70% in the irradiation group, while the 1-year survival rate was only 15% in the chemotherapy group. These data strongly suggest that, in polymorphic reticulosis, initial chemotherapy may be very toxic.