The conundrum of parapsoriasis versus patch stage of mycosis fungoides.

Terminological confusion with benign dermatosis, such as parapsoriasis en plaques, makes it difficult to diagnose mycosis fungoides in the early patch stage. Early diagnosis of mycosis fungoides (MF) is important for deciding on type of therapy, prognosis and for further follow-up. However, until recently, there has been no consensus on criteria that would help in diagnosing the disease early. Some believe that large plaque parapsoriasis (LPP) should be classified with early patch stage of MF and should be treated aggressively. However, there is no firm clinical or laboratory criteria to predict which LPP will progress to MF and we can only discuss about statistical probability. Moreover, long-term outcome analysis of even patch stage of MF is similar to that of control population. We therefore believe that LPP should be considered as a separate entity at least to prevent the patient from being given a frightening diagnosis. We also feel that patients need not be treated with aggressive therapy for LPP and will need only a close follow-up. This article emphasizes the criteria for diagnosing early MF and has highlighted the importance of considering LPP as a distinct benign entity.