Morphologic heterogeneity of malignant lymphomas developing in mycosis fungoides

From an extensive series of patients with mycosis fungoides, we identified 12 in whom subsequently developing extracutaneous (lymph nodal) lymphoma manifested morphologic features other than those of so-called cutaneous T-cell lymphoma. Six patients had features diagnostic of Hodgkin's disease, two had morphologic and cytochemical features consistent with T-cell lymphoma but without the morphologic features ascribed to cutaneous T-cell type, and four had morphologic characteristics most consistent with B-cell lymphoma. Although in most cases of mycosis fungoides the lymphomas exhibit morphologically distinctive features of mycosis cells, we propose that in occasional cases this morphologic correlation is not present.