Department of Skin & VD, SBH Govt Medical College, Chakkarbardi, Dhule, Maharashtra, India.
Int J Dermatol. 2019 Jun;58(6):729-732. doi: 10.1111/ijd.14274. Epub 2018 Oct 21.
Leprosy is a chronic granulomatous disease caused by M. leprae. It is a great imitator as it can manifest in different unusual and atypical ways. Mid borderline leprosy (BB) is an unstable form representing the immunologic midpoint in the clinical spectrum.
Here, we report a case of BB leprosy having classical inverted saucer-shaped lesions elsewhere on the body with a linear psoriasiform lesion over the left forearm following the lines of Blaschko. Biopsy from this lesion revealed granulomas consisting of equal admixture of epithelioid cells and macrophages without multinucleate giant cells suggesting mid borderline leprosy.
Occurrence of lesions in a Blaschko linear pattern supports the role of genetic susceptibility to leprosy. The genetically vulnerable cells along the lines of Blaschko were infected while the surrounding cells remained unaffected. This explains the concept of locus minoris resistentiae due to cutaneous mosaicism.
麻风病是由麻风分枝杆菌引起的慢性肉芽肿性疾病。它是一种极具模仿性的疾病，因为它可以以不同的不寻常和非典型方式表现出来。中间界限型麻风（BB）是一种不稳定的形式，代表临床谱系中免疫的中点。
在这里，我们报告了一例 BB 麻风病的病例，该患者在身体其他部位有典型的倒碟形病变，左前臂有线性银屑病样病变，沿着 Blaschko 线分布。该病变的活检显示肉芽肿，由等量的上皮样细胞和巨噬细胞混合组成，没有多核巨细胞，提示为中间界限型麻风。
病变呈 Blaschko 线性模式出现支持麻风病易感性的遗传作用。沿着 Blaschko 线的遗传易感细胞受到感染，而周围的细胞不受影响。这解释了由于皮肤马赛克现象导致的 locus minoris resistentiae 概念。
