Mycosis fungoides: disease evolution of the "lion queen" revisited.

Mycosis fungoides (MF), which represents the most common subtype of primary cutaneous T-cell lymphoma (CTCL), is an epidermotropic lymphoma included as an indolent form in the recent WHO/EORTC classification. From a clinical point of view, the classic disease progression usually is slow and takes over years or even decades, and characterized by the evolution from patches to more infiltrated plaques and eventually to tumours or erythroderma. However, the analysis of the MF disease course has been greatly impaired by the rarity of the disease, thus data about the time course of disease progression and pattern of relapse during time are not well known. In this review, a summary of published data on MF large patients cohorts will be presented, together with the results obtained by a retrospective analysis of clinical features and follow-up data of 1,422 MF patients diagnosed and followed-up from 1975 to 2010 in 27 Italian Centres (Italian Study Group for Cutaneous Lymphoma). From a clinical perspective, the amount of data support the relevance of a stage-tailored, differentiated follow-up strategy, in as much as the TNMB staging appears not only to be associated with different progression rates, but also shows as a new finding a relationship with different patterns of disease progression. From a biological point of view, there is the need to understand the molecular basis of the different clinical pathways of disease progression, to be able to potentially identify at an earlier phase of disease evolution, the patients who are more likely to develop erythroderma or tumour-stage progression. In conclusion, if MF is indeed a true "lion queen", as dermatologists we need to be expert and wise tamers to keep it under control.