Evolution of Dupilumab-Associated Cutaneous Atypical Lymphoid Infiltrates.

Background: Observations highlighting the "unmasking" of cutaneous T-cell lymphoma after treatment with dupilumab for atopic dermatitis (AD) have been recently reported. However, there remains a paucity of literature describing the evolution of clinical and histopathological features that characterizes this phenomenon.

Objective: To define the clinical and histopathologic evolution of atypical lymphoid infiltrates after the administration of dupilumab for AD.

Methods: A cross-sectional study of clinical and histopathologic features in 7 consecutive patients with a diagnosis of "atypical lymphoid infiltrate" or mycosis fungoides (MF) on dupilumab for AD was performed.

Results: Seven patients with atypical lymphoid infiltrates or MF in evolution after dupilumab therapy (age range 27-74 years) were reviewed. Average duration of AD before MF diagnosis was 5.7 years, and the average duration on dupilumab treatment was 9.8 months. Notable histopathologic features across predupilumab and postdupilumab biopsies included progressive increase in the densities of the atypical lymphoid infiltrates (7/7), presence of atypical epidermotropic lymphocytes (6/7), and papillary dermal fibrosis (6/7).

Limitations: Small retrospective cohort study.

Conclusion: These cases highlight the transformation of lymphoid infiltrates after dupilumab treatment for AD and emphasize the importance of clinical and histopathologic evaluation before and during treatment with dupilumab for treatment-refractory presumed AD.