Monoclonal gammopathy and mycosis fungoides. Report of four cases and review of the literature.

Of four patients with mycosis fungoides and monoclonal gammopathy, one died of multiple myeloma that developed 4 years after the mycosis fungoides. The other three had monoclonal gammopathy of undetermined significance. This association does not appear to occur with a high frequency in patients with mycosis fungoides than in the general population. However, it demonstrates that B cell proliferation can occur in patients with primary cutaneous T cell disease.