Vertical vs. Transverse Sections in Alopecia Biopsy Diagnosis

In the 2005 document, Dirk M. Elston, MD, evaluates the use of vertical versus transverse sections in alopecia biopsy diagnosis. He argues that while a consensus statement favored transverse sections, there is no data comparing the diagnostic yield of both methods. Elston, with experience in both the pathology laboratory and clinic, suggests that each method has its advantages: transverse sections are useful for quantitative data and assessing non-scarring alopecias, while vertical sections are better for evaluating scarring alopecias. He recommends using both techniques to improve diagnostic accuracy and reduce the need for multiple biopsies. A study by Sinclair and coworkers is mentioned, indicating that a single transverse biopsy matched the diagnosis of three biopsies in 79% of cases, with additional biopsies adding value in 21% of cases. Elston concludes that both sectioning methods are acceptable with adequate step sectioning, but having both types of sections is preferable to maximize diagnostic yield, with transverse sections being favored for pattern alopecia, telogen effluvium, or trichoptilosis, and vertical sections for scarring alopecia and when full thickness skin changes are significant.