In 10 cases of cutaneous lymphomas, outflow of nuclear material into the cytoplasm of tumoral cells was observed ultrastructurally. Various stages of this phenomenon could be visualized. These observations were made in various types of epidermotropic and non epidermotropic cutaneous lymphomas but they are particularly evident in Crosti’s reticulosis. These nuclear abnormalities were observed prior to any treatment; they are unrelated with tissue preparation and are very different from the well-known nuclear degeneration processes. They have been observed in various but exceptional physiological or pathological conditions, but have apparently not been noticed in earlier works on cutaneous lymphomas, except in 1 case of Crosti’s reticulosis. No prognostic implication of these images was found. Their significance is not clear, but could be related with mitotic disord