'Cutting Through the Roots': A Critical Appraisal of Transverse and Vertical Sectioning Techniques of Scalp Biopsy for Primary Alopecia.

Alopecia, a prevalent and distressing condition with diverse aetiologies, encompasses both scarring and non-scarring types and necessitates accurate diagnostic approaches for effective management. Apart from optimal biopsy site selection based on clinical suspicion, such as active borders for scarring alopecias and lesion borders for non-scarring alopecias, choice of appropriate method for grossing of alopecic scalp biopsies also forms a key step. Historically, debates on 'One (biopsy) Vs Two (biopsies)' and 'Vertical/Longitudinal Vs Horizontal/Transverse' sections persist, each approach carrying its advantages and disadvantages. Traditional methods, such as those proposed by Headington and Whiting, describe the landmarks for slicing a biopsy for transverse section. Newer innovative strategies, including the HoVert technique and the Tyler technique, aim to obtain both vertical and horizontal sections from a single biopsy. This article meticulously presents all the methodologies employed in the grossing of alopecic scalp biopsies in a simplified manner, presents a comprehensive overview of their strengths and limitations, and offers evidence-based recommendation for choosing optimal grossing techniques based on clinical scenarios.