Mycosis fungoides: an updated review of clinicopathologic variants.

Mycosis fungoides (MF) is the most common primary cutaneous T-cell lymphoma. Although it was first described in 1833, our understanding of this disease has continued to evolve. From a diagnostic perspective, the diagnosis of MF can be challenging particularly in the early stages of the disease, because of overlap between the histological features of early MF lesions and many other inflammatory dermatoses. Furthermore, there has been an emergence of numerous clinicopathologic and immunohistochemical variants of MF reported in the literature. Although the prognostic significance of some of the rare variants is still not fully understood, certain variants, such as folliculotropic and bullous MF, have demonstrated less indolent clinical courses compared with classic MF and necessitate aggressive therapeutic measures. Thus, it is important for dermatologists and dermatopathologists to be knowledgeable of the widely varied clinical, histological, and immunohistochemical presentations of MF to arrive at a prompt and accurate diagnosis and initiate appropriate treatment.