Ex vivo dermatoscopy of scalp specimens and slides

Correct evaluation of horizontal scalp biopsies requires accurate gross sectioning and embedding of the tissue. The most common issue during processing includes incorrect specimen bisection.

To verify if (i) ex vivo assessment of scalp biopsies by contact dermatoscopy can identify the correct plane of transverse bisection as well as (ii) if using contact dermatoscopy on the glass slides can be useful to control the tissue processing and expedite sign-out.

For the first aim, dermatoscopic pictures of 43 scalp biopsies were printed and shown to 10 dermatology residents not involved in the study, who were asked to identify and highlight the dermo-epidermal junction. For the second aim, dermatoscopic captions of 40 horizontal sections were evaluated in a blinded way for the size of the specimen as well as the level and plane of bisection. The agreement was investigated using Cohen's κ statistics.

Ten independent observers were able to correctly identify the dermo-epidermal junction as a brownish wavy line in 95.3% cases. The Cohen's κ statistics showed almost perfect agreement. Two independent pathologists agreed on the specimen size in all cases, on the specimen plane in 39 cases and on the specimen level on 35 cases. The Cohen's κ statistics showed almost complete agreement for the size and plane of bisection and substantial agreement for the level of section.

Ex vivo dermatoscopy of scalp biopsies may be a new way to decrease laboratory costs and improve turnaround time in hair pathology as this technique optimally guides the correct bisection at 1-1.5 mm below the junction. Ex vivo dermatoscopy on the slides may expedite sign out after the initial bisection.