151 Computer Assisted Histomorphometric Evaluation of Scalp Biopsy

D. Shum, M. Martinka, O. Bernaldo, H. Lui, J. Shapiro. Division of Dermatology, the University of British Columbia, British Columbia, Canada.

A major challenge in the histopathologic examination of scalp biopsies is to adequately visualize and evaluate as many of the hair follicles present in the tissue. While routine vertical sections are easier to process and exhibit familiar histological landscape, oblique orientation of the follicular structures precludes any means of quantification even if multiple serial vertical sections are available. To improve on the diagnostic yield of conventional vertical sections, the use of transverse sections of a scalp punch has been suggested. An obvious disadvantage of transverse sectioning is that a very limited cross-section of each follicle is shown in each microscopic section. Numerous sections are needed to demonstrate the follicles in their entirety and to determine follicular growth activity. In the management of patients with alopecia, accurate morphometric analysis of hair growth is required. Recent advances in PC-based computing have enabled efficient processing of large number of images and this technology is well suited for the study of transverse sections of scalp biopsies. To ensure complete coverage of all the follicular structures, scalp biopsies from 12 patients with non-inflammatory, non-scarring alopecia have been serially sectioned in 0.05 to 0.1mm interval, resulting in 30 to 70 sections in average for each case. Three dimensional reconstruction imaging softwares are then used to evaluate and quantify the follicular structures, and the results are analysed. In addition, a computer generated 3 dimensional model of each biopsy tissue core is generated, allowing easy visualisation of all hair structures. Our data suggest that the anatomy of follicular structures and scalp hairs, including density and diameter, is more variable than previously reported. Up to 60 hairs have been counted in a 4.0mm punch and our 3D models demonstrate the occasional merging of follicular infundibulae and existence of dystrophic follicular units. Patients with non-scarring, non-inflammatory alopecia may suffer from overlap of diseases, which can only be revealed by detailed histomorphometric studies. We believe computer assisted analysis of the scalp biopsy is the best means to further quantify variations of human scalp hair and to diagnose, as well as manage patients with hair disorders.