Bond R, Hendricks A, Patterson-Kane J, Stevens K, Brooks Brownlie H W
Department of Clinical Sciences and Services, Royal Veterinary College, Hawkshead Lane, North Mymms, Hatfield, Herts, AL9 7TA, UK.
Department of Veterinary Pathology, University of Glasgow Veterinary School, Bearsden Road, Bearsden, Glasgow, UK.
J Small Anim Pract. 2021 Apr;62(4):244-252. doi: 10.1111/jsap.13243. Epub 2020 Oct 12.
Transverse sectioning of skin biopsy specimens has revolutionised assessment of human alopecia by demonstration of every hair in each specimen, allowing quantitative evaluation of follicular activity. Since only vertical sectioning is performed routinely in veterinary laboratories, we aimed to determine whether transverse sectioning was a valuable technique in assessment of canine alopecia.
Paired vertical and transverse sections of biopsy specimens from 31 alopecic dogs were examined independently in triplicate in random order and blinded to previous diagnosis using a standard check-list proforma. Assessments of key features (follicular activity [anagen/telogen], infundibular hyperkeratosis, sebaceous gland abnormalities, pigment clumping, dermal inflammation) by each sectioning method were compared.
In the 31 cases, (atrophic [n = 13], dysplastic [n = 12], inflammatory diseases [n = 6]), follicular inactivity scores (median, [lower-upper quartile]) in transverse sections significantly exceeded those in vertical sections (transverse 4 [3-5], vertical 3 [2-4]). Agreement between the two sectioning planes was moderate for infundibular hyperkeratosis (kappa = 0.5210) and dermal inflammation (0.4351), fair for sebaceous gland abnormalities (0.3966) and pigment clumping (0.2197), but slight for follicular activity (0.1041). Vertical sectioning demonstrated diagnostically important epidermal pathology (n = 2) and dermal thinning (n = 3) whereas transverse sectioning enhanced assessment of hair growth phase (n = 11), follicular structure and architecture (n = 11), and focal luminal or mural folliculitides (n = 3).
Transverse sectioning confers significant benefits and complements traditional vertical sectioning in the histological assessment of canine hair follicle diseases, particularly when subtle abnormalities comprise distorted compound follicle architecture, hair cycle arrest or when relatively few adnexal structures are affected.
皮肤活检标本的横切技术通过展示每个标本中的每一根毛发，彻底改变了人类脱发的评估方式，使得对毛囊活性进行定量评估成为可能。由于兽医实验室通常只进行纵切，我们旨在确定横切在犬类脱发评估中是否是一项有价值的技术。
对31只患秃毛症犬的活检标本进行配对纵切和横切，由三人独立以随机顺序检查，并根据标准检查表模板进行评估，且评估人员对先前的诊断不知情。比较了每种切片方法对关键特征（毛囊活性[生长期/休止期]、漏斗部角化过度、皮脂腺异常、色素沉着、真皮炎症）的评估结果。
在这31例病例中（萎缩性[n = 13]、发育异常性[n = 12]、炎症性疾病[n = 6]），横切标本中的毛囊无活性评分（中位数，[下四分位数-上四分位数]）显著高于纵切标本（横切4[3 - 5]，纵切3[2 - 4]）。两种切片平面在漏斗部角化过度（kappa = 0.5210）和真皮炎症（0.4351）方面的一致性为中等，在皮脂腺异常（0.3966）和色素沉着（0.2197）方面为一般，但在毛囊活性方面较弱（0.1041）。纵切显示出具有诊断意义的表皮病变（n = 2）和真皮变薄（n = 3），而横切则增强了对毛发生长阶段（n = 11）、毛囊结构和构造（n = 11）以及局灶性管腔或壁部毛囊炎（n = 3）的评估。
在犬毛囊疾病的组织学评估中，横切具有显著优势，并能补充传统的纵切，特别是当细微异常包括复合毛囊结构扭曲、毛发周期停滞或附属结构受影响较少时。
