Shamim, Huma

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.

Background: Folliculotropic mycosis fungoides (FMF) is a variant of cutaneous T-cell lymphoma that has clinical overlap with a variety of inflammatory follicular unit disorders. However, we describe distinctive presentations of FMF with acneiform features that can be diagnostically challenging, leading to diagnostic delay. Objective: To highlight the importance of histopathologic and immunohistochemical evaluation for diagnostic confirmation of presumed inflammatory follicular unit–based disorders that are unusual in presentation or unresponsive to standard therapies. Methods: A cross-sectional retrospective study of 5 consecutive patients with a histopathologic diagnosis of FMF was conducted. The clinical, histopathologic, immunophenotypic, and molecular genetic features of cases are presented. Results: We describe 5 patients with clinical and histopathologic presentations of FMF masquerading as hidradenitis suppurativa, furunculosis, or acne vulgaris (age range 34–66 years, 4:1 female to male). Clinical morphologies included open and closed comedones, inflammatory pustules, papules and nodules, follicular papules with keratotic plugging, cysts, and scarring involving the face, trunk, and intertriginous areas. All patients failed to respond to standard therapies, including topical and oral antibiotics, topical and oral retinoids, or topical corticosteroids, before receiving the diagnosis of FMF. Lesional skin biopsies showed a perifollicular CD4-positive T-lymphocytic infiltrate with pilotropism, intrafollicular mucin deposition, foreign-body granulomatous inflammation, acute inflammation, and follicular epithelial necrosis. None had concurrent systemic mycosis fungoides. Limitations: Small retrospective cohort study. Conclusion: We present these cases to expand the clinical and histopathologic spectrum of FMF that may strikingly resemble acneiform disorders and to highlight the importance of diagnostic reconsideration with histopathologic evaluation.

AbstractBackgroundMycosis fungoides (MF) is characterized by epidermotropic atypical lymphocytes in the absence of spongiosis. However, we describe an unusual presentation of MF with spongiosis, mimicking benign inflammatory dermatoses and highlight the importance of pathologic interpretation for diagnostic confirmation.MethodsA cross‐sectional study of consecutive patients diagnosed with MF with spongiosis was conducted. The clinical, histopathologic, immunophenotypic, and molecular genetic features of cases were reviewed.ResultsWe identified nine cases of MF (age range 34‐82 years; mean 75 years), with an initial diagnosis of dermatitis (6/9), psoriasis (4/9), or other inflammatory dermatoses (2/9). Pruritus, pain, and blisters were common clinical manifestations. The most common areas of involvement were the extremities (8/9). Epidermotropism with spongiosis was a central histopathological feature in all cases.ConclusionThese cases highlight prominent spongiosis in MF and overlap with common benign inflammatory dermatoses. We present these cases to show the diagnostic pitfalls associated with spongiotic presentations of MF. Dermatitis, psoriasis, and other inflammatory skin conditions not responsive to standard therapy warrant further work‐up including biopsy to rule out MF. Multiple skin biopsies and review by a dermatopathologist with expertise in the diagnosis of cutaneous lymphoma is highly recommended.