自从在日常实践中越来越多地使用 dupilumab 治疗特应性皮炎 (AD) 以来，已经报道了几例发生皮肤 T 细胞淋巴瘤 (CTCL) 和淋巴浸润的病例。旨在深入了解 AD 患者的临床和组织病理学特征在dupilumab治疗期间临床怀疑患有CTCL。该回顾性观察病例系列包括2017年10月至2022年7月在荷兰乌得勒支大学医学中心接受dupilumab治疗的成人（≥18岁）AD患者。相关患者、疾病和治疗特征进行了评估。收集并重新评估治疗前、治疗期间和治疗后的皮肤活检。纳入了 14 名中位 (IQR) 年龄为 56 (36-66) 岁的疑似 CTCL 患者（54.5% 男性），且在 dupilumab 治疗期间症状恶化。 14 名患者中，有 3 名被回顾性诊断为先前存在的蕈样肉芽肿 (MF)。 11 名 AD 患者最终被诊断为淋巴反应 (LR)。这些患者表现出类似 MF 的症状；然而，组织病理学结果不同，包括上表皮部分散布分布的小深染淋巴细胞、CD4:CD8 比例失调和 CD30 过度表达，但没有 CD2/CD3/CD5 丢失。临床恶化的中位时间为 4.0 个月（IQR，1.4-10.0）。治疗后活检显示所有患者的 LR 完全清除。这项研究发现 dupilumab 治疗可导致可逆的良性 LR，类似于 CTCL，但具有独特的组织病理学特征。

Since the increased use of dupilumab for atopic dermatitis (AD) in daily practice, several cases have been reported on the development of cutaneous T-cell lymphomas (CTCL) and lymphoid infiltrates.To provide insight in the clinical and histopathologic features of patients with AD clinically suspected for CTCL during dupilumab treatment.This retrospective observational case series included adult (≥18 years) patients with AD treated with dupilumab between October 2017 and July 2022 at the University Medical Center Utrecht in the Netherlands.Relevant patient, disease, and treatment characteristics were evaluated. Skin biopsies before, during, and after treatment were collected and reassessed.Fourteen patients (54.5% male) with a median (IQR) age of 56 (36-66) years suspected for CTCL with deterioration of symptoms during dupilumab treatment were included. Of 14 patients, 3 were retrospectively diagnosed with preexistent mycosis fungoides (MF). Eleven patients with AD were eventually diagnosed with a lymphoid reaction (LR). These patients showed MF-like symptoms; however, histopathologic findings were different, and included sprinkled distribution of small hyperchromatic lymphocytes in the upper epidermal section, a dysregulated CD4:CD8 ratio, and CD30 overexpression, without loss of CD2/CD3/CD5. The median time to clinical worsening was 4.0 months (IQR, 1.4-10.0). Posttreatment biopsies showed complete clearance of the LR in all patients.This study found that dupilumab treatment can cause a reversible and benign LR, which mimics a CTCL, though has distinctive histopathologic features.