Lichenoid changes in mycosis fungoides

Background: The lichenoid tissue reaction (LTR) is present in a variety of dermatoses. Numerous histologic variants of mycosis fungoides (MF) have also been described. Objective: Our purpose was to analyze a subset of patients with mycosis fungoides (MF) who had a prominent LTR at the time of presentation. Methods: Clinical and pathologic features were evaluated in 12 patients with MF and an LTR. Results: The primary complaint was intense pruritus (in 10 of 12 patients). An accelerated course was noted in one half of the patients including four with Sezary syndrome. Four patients died: two with Sezary syndrome and two with extensive patch/plaque MF. Lymphocyte atypia, prominent basal cell layer epidermotropism, and the presence of plasma cells and eosinophils may help to distinguish lichenoid MF from lichen planus. Conclusion: A subset of patients with MF present with lichenoid changes. The pathologic features may have a striking resemblance to lichen planus. Our findings suggest that lichenoid changes in MF tend to be associated with intense pruritus and may connote a poor prognosis.