RESUMO
Dermatofibroma progressive and recurrent, described by Darier and Ferrand in 1924 is a tumour that grows slowly, and can invade the whole dermis, sectors of the conjunctival interlobular hypodermic tracts, superficial muscular fascia and invade striated muscular fibers, lymphatic ganglia and bones. The most frequent localization is the back and abdomen although it an be seen in other sits of the skin. Ulceration is not frequent. Usually it is most resistant to therapy and recidives frequently. As it is not radio sensible the treatment of first choice is surgery. The evolution is very slow, from months to twenty or more years. We communicate a case of dermatofibroma recurrent of Darier and Ferrand localized in the left supra spinal region, that ulcerated when patient was irradiated with cobalt because she had a lung adenocarcinoma. Possibility radiotherapy produced an alteration in the immunological state of the patient producing by this mechanism the ulceration of the DF.