[Parapsoriasis--to be or not be (mycosis fungoides)]

Mycosis fungoides (MF) is the most prevalent cutaneous lymphoma, characterized by uncontrolled growth of T cells within the skin. The diagnosis in the early stages may be difficult, since, in these stages, the disease can imitate benign inflammatory processes, both clinically and histologically. One of the difficulties in determining diagnostic criteria for early MF is the existing terminology of parapsoriasis. There is disagreement concerning the exact definition and whether it is a chronic benign condition with similar clinical and histological characteristics as MF, or rather it is part of the disease spectrum itself. There is a need for uniformity in the definition for treatment decisions, for epidemiological purposes and for clinical and experimental research. This article reviews the different approaches to parapsoriasis as part of MF over the years.