高嗜酸综合征（HES）是一组异质性疾病，特征为持续性高嗜酸性白细胞增多和内脏损害。FIP1L1-PDGFRA（F/P）融合基因在3-25%的HES患者中发现，是髓系肿瘤引起克隆性嗜酸细胞增多的致癌驱动因素。虽然皮肤症状是F/P HES患者最常见的症状类型，但组织学报告很少。本文介绍了一名78岁男性患者，其躯干和四肢上有红斑和严重瘙痒。实验室检查显示显著的嗜酸性白细胞增多和血清维生素B12升高。组织学检查显示上皮下血管周围有大量嗜酸性白细胞和肥大细胞浸润。荧光原位杂交技术在外周血和皮肤病变核中检测到了F/P融合基因。该患者被诊断为F/P HES，并对伊马替尼表现出优异的临床和血液学反应。©作者（们）2022年。由牛津大学出版社代表英国皮肤病学协会出版。保留所有权利。如需授权，请发送电子邮件至：journals.permissions@oup.com。

Hypereosinophilic syndrome (HES) is a heterogeneous group of diseases, characterized by persistent hypereosinophilia and end-organ damage. The FIP1L1-PDGFRA (F/P) fusion gene is found in 3-25% of patients with HES and is an oncogenic driver of myeloid neoplasms with clonal eosinophilia. Although cutaneous symptoms are the most common type of symptom in patients who have F/P fusion gene-positive HES (F/P HES), histological reports are limited. We herein present the case of a 78-year-old man with erythematous macules and severe pruritus on his trunk and extremities. Laboratory investigations revealed marked eosinophilia and elevated serum vitamin B12. A histological examination showed massive infiltration of eosinophils and mast cells around the vessels in the upper dermis. Fluorescence in situ hybridization revealed F/P fusion genes in nuclei in the peripheral blood and the skin lesion. The patient was diagnosed with F/P HES, and showed an excellent clinical and haematological response to imatinib.© The Author(s) 2022. Published by Oxford University Press on behalf of British Association of Dermatologists. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.