Because of our personal experience with the two patients just recorded, we were prompted to reflect on the matter of "hypopigmented mycosis fungoides." Several questions inevitably came to mind. Among them were these: Is hypopigmented mycosis fungoides an authentic manifestation of that lymphoma? Can mycosis fungoides present itself solely as hypopigmented macules and patches? And if the answer to the question is "yes," is there a hyperpigmented analogue of hypopigmented mycosis fungoides? Are there pitfalls, clinically and histopathologically, in diagnosis of mycosis fungoides with hypopigmentation? What is the explanation for hypopigmentation in mycosis fungoides? Do pigmentary changes in mycosis fungoides have implications for prognosis?