进行性斑状色素减少症的临床及实验研究

Clinical and experimental studies on progressive macular hypomelanosis

目的探讨进行性斑状色素减少症（PMH）的临床特点和诊断要点。方法用Wood灯及活体共聚焦激光扫描显微镜（皮肤CT）观察皮损特点、致病菌培养、黑素细胞培养，并应用S-100和TRP-1免疫组化分析皮损区黑素细胞数量、电镜观察其超微结构特征。结果Wood灯检查示皮损区可见点状红色荧光，皮肤CT观察示皮损区色素环完整，但与周围正常皮肤相比其内所含的黑素颗粒含量减少。致病菌培养可见产红色荧光的革兰阳性棒状杆菌，经鉴定为痤疮丙酸杆菌。S-100染色示皮损区阳性细胞数（8．25±0．96）与周围正常皮肤（8．75±1．71）相比无统计学意义（P〉0．05）。TRP-1染色示皮损区阳性细胞数（4．25±0．96）与周围正常皮肤（4．50±1．29）相比也无统计学意义（P〉0．05）。电镜观察发现，皮损区Ⅳ期黑素小体的数量明显下降，并观察到较多的膜结合体，内含成簇状分布的多个体积较小的Ⅱ～Ⅳ期黑素小体。成功培养出黑素细胞，其形态与正常细胞相比未见明显异常。结论初步提出进行性斑状色素减少症的诊断要点。

Objective To assess the clinical features and diagnostic index of progressive macular hypomelanosis （PMH）. Methods Eight patients with PMH were recruited into this study. Wood＇s lamp and in vivo confocal laser scanning microscopy （CLSM） were utilized to observe the lesions of all patients. Micro- biological culture of lesion specimens from 2 patients was performed. Tissue specimens from 4 patients underwent immnnohistochemical staining witb anti-S-100 and anti-TRP-1 antibodies for the detection of melanocyte quantity. Electron microscopy was utilized to observe ultrastructural features of lesions. Primary culture of melanocytes was carried out with lesional epidermis. Results Under Wood＇s lamp, the lesions of PMH showed punctiform red fluorescence. CLSM revealed complete pigmented rings in lesions with decreased melanin granules compared with those surrounding normal skin. Microbiological culture grew red fluorescence-producing, gram-positive bacillus which was identified as Propionibacterium aches. Immunohistochemistry showed no significant difference in the number of S-100-postive cells or TRP-1-positive ceils per high power field （x 400） between lesions and surrounding normal skin （8.25 ＋ 0.96 vs 8.75 ＋ 1.71, 4.25 ＋ 0.96 vs 4.50 ＋ 1.29, both P 〉 0.05）. Uhrastructural studies showed a large reduction in the number of type Ⅳ melanosomes in lesions of PMH, along with numerous membrane bound bodies and clusteredly distributed, small type Ⅱ-Ⅳ melanosomes. Melanocytes, with morphological similarity to normal melanocytes, were successfully isolated from the lesional tissue, cultured and identified. Conclusion A primary diagnostic criteria is proposed for PMH according to the clinical and experimental studies.