黄褐斑患者组织病理特征分析

目的 探讨黄褐斑组与正常对照组组织病理学及超微结构差异。方法 分别取8例黄褐斑患者的皮损组织，16例面部色素痣皮损周围正常组织，分别取2 mm活检，进行HE染色、Fontana?Masson染色、Verhoeff?van Gieson染色，HMB45、NKI/beteb免疫组化及透射电镜观察。光镜下半定量及计算机图像定量分析。结果 黄褐斑组组织病理表现为以基底层、棘层为主的黑素颗粒增多，部分伴真皮黑素颗粒增加。黄褐斑组黑素细胞仅存在于表皮层，较正常皮肤黑素细胞数量无增加，但表皮层黑素细胞体积增大，染色强度增加，树突增多。8例黄褐斑患者均在真皮浅层及毛细血管周围观察到轻到中度的淋巴细胞浸润，8例黄褐斑患者均在真皮浅层观察到轻到中度的毛细血管扩张。电镜：黄褐斑组黑素细胞，角质形成细胞内都含有更多黑素小体，此外，还观察到黑素细胞树突伸入到真皮层。结论 8例黄褐斑患者中，仅有表皮型和混合型（表皮真皮型）2型，无单纯真皮型黄褐斑。炎症反应、毛细血管扩张可能引发或加重黄褐斑。

Histopathological characteristics of melasma

Zhu Liping, Pang Qin, Lyu Lechun, Yi Shuitao, Ding Dongmei, He Li Department of Dermatology, First Affiliated Hospital of Kunming Medical University, Kunming 650032, China （Zhu LP, Lyu LC, Yi ST, Ding DM）; Outpatient Department, Winona Cosmetic-Dermatology Center, Kunming 650000, China （Pang Q）; Department of Dermatology, First Affiliated Hospital of Kunming Medical University, Institute of Dermatology and Venereology of Yunnan Province, Engineering Research Center of Yunnan Province, Kunming 650032, China （He L） Corresponding author: He Li, Email: drheli2662@126.com 【Abstract】 Objective To investigate histopathological and ultrastructural differences between melasma tissues and normal skin tissues around pigmented nevus. Methods Eight patients with melasma and 16 patients with facial pigmented nevus were included in this study. Two millimeter punch biopsies were taken from melasma lesions and adjacent normal skin of facial pigmented nevus. Biopsy specimens were then subjected to hematoxylin-eosin （HE） staining, Fonton-Masson staining, Verhoeff-van Gieson staining, and immunohistochemical staining with monoclonal antibodies HMB45 and NKI/beteb. Transmission electron microscopy was used to observe the tissue specimens. Semi-quantitative analysis was performed under a light microscope, and quantitative analysis by using a computerized image analysis system. Results Histopathological study revealed increased number of melanin granules mainly in the basal and prickle cell layers, sometimes in the dermis, in melasma tissues compared with normal skin tissues. Melanocytes were only observed in the epidermis of melasma tissues. Compared with normal skin tissues, melasma tissues showed no significant difference in the quantity of melanocytes, but a significant increase in the volume, staining intensity and dendrite number of melanocytes. In all of the 8 patients with melasma, mild to moderate lymphocytic infiltration was observed in the superficial dermis and around capillaries, with moderate telangiectasis in the superficial dermis. Electron microscopy revealed that there were more melanosomes in melanocytes and keratinocytes, and melanocyte dendrites extended into the dermis in melasma tissues. Conclusions Among the 8 patients, there were only two types of melasma, i.e., epidermal melasma and mixed melasma, and no dermal melasma was found. Inflammation and telangiectasis may induce or aggravate melasma.