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.