Correlations between clinical and pathological features in 17 cases of mycosis fungoides before and after transformation

Abstract

Mycosis fungoides (MF) may progress to transformed MF (T-MF), a condition with aggressive behavior. This study was designed to compare the clinical and pathological features of biopsies in 17 cases of MF before and after transformation. During a revision of primary cutaneous T cell lymphomas, 53 cases of MF were identified, including 17 cases of T-MF. Clinical, pathological, and immunohistochemical data for the MF patients were evaluated. Cases of T-MF and intermediate transformed (IT) MF were diagnosed according to previous criteria. The histological and immunohistochemical features of T-MF biopsies were compared with those of MF/IT-MF biopsies taken before or concomitant with transformation. At the initial diagnosis, three patients were found to have more advanced stages of disease: two had MF and T-MF simultaneously, and another had only oral T-MF. Four patients considered to show histological transformation maintained disease stages Ia and Ib and all remain alive. Of five patients with IT-MF at first diagnosis, all progressed to complete histological transformation, three developed tumors, and two died of disease. Four patients progressed to CD30+ large cell lymphoma, and three of these died of disease. In one of these patients, the MF biopsy showed a high level of expression of CD30 in the epidermis and dermis. No correlation between advanced MF and expression of CD25 and CD30, or frequency of Ki-67+ cells was found. The frequency of transformation among patients with initially non-transformed MF was high. Our findings support the emphasis given by other authors to IT-MF, a pattern of MF which is generally not considered in many studies.