Folliculotropic mycosis fungoides in a psoriatic patient under methotrexate treatment

Abstract

SummaryFolliculotropic mycosis fungoides is a variant of mycosis fungoides with a worse prognosis than the classic form. It can be associated with follicular mucinosis. We report a case of folliculotropic mycosis fungoides developing in the months following methotrexate therapy in a psoriatic patient. This lymphoma did not regress after stopping the antipsoriatic treatment. There is a known relationship between the use of immunosuppressive therapies and the development of lymphoproliferative malignancies. However these lymphomas are mainly B‐cell non‐Hodgkin lymphomas associated with Epstein‐Barr virus. In our patient the short period of time from the beginning of the immunosuppressive treatment to the occurrence of the T‐cell lymphoma does not support a strong causal relationship between the drug intake and the development of mycosis fungoides. To the best of our knowledge, this is the first case of folliculotropic mycosis fungoides in a patient treated with methotrexate for psoriasis.