The Horizontally Sectioned Scalp Biopsy: What to include in the biopsy report?

Components of the Scalp Biopsy Report

A scalp biopsy is a short procedure that allows a cylinder of skin to be obtained from the scalp. This cylinder can then be cut into very thin ‘slices’ and examined under the microscope. There are two main ways that a scalp biopsy can be processed - 1) vertically and 2) horizontally (also known as 'transversely’). Both have their advantages and disadvantages and a skilled expert pathologist can usually make accurate diagnoses using either technique.

The Horizontally Sectioned Biopsy

There may be several distinct advantages to the horizontal biopsy including the ability to obtain follicular counts and the ability to determine the number of hairs in anagen phase, catagen phase as well as the number of hairs in the biopsy that are terminal hairs and vellus hairs. From these numbers one can determine the percent of hairs in telogen phase and the T:V ratio which provides helpful information in assessing non scarring alopecias such as telogen effluvium and androgenetic alopecia.

Evaluation of biopsies is enhanced by evaluation of follicles at the level of the isthmus, the infundibulum and the bulb.  

Components of a Complete Report.

 The main point of this article is to review exactly what information should iIdeally be included in a complete pathology report.

A report should include information on:

1.   Number of hair follicles seen

2.   Number of terminal hairs seen

3.   Number of vellus hairs seen

4.   Number of anagen hairs seen

5.   Number of catagen and telogen hairs seen

6.   Confirmation of the presence or reduction/absence of sebaceous glands

7.   Assessment for inflammation and, if present, the degree of inflammation and the level of the skin where the inflammation is found 

a.   Presence or absence of inflammation in the isthmus

b.   Presence or absence of inflammation around the bulb (peribulbar inflammation)

c.    Presence or absence of perivascular inflammation

d.   Presence or absence of lichenoid inflammation in the epidermis

e.   Presence or absence of lichenoid inflammation in the outer root sheath

f.     Presence of inflammation in fibrous tracts/stellae including whether they contain eosinophils

8.   Confirmation of the presence or absence of fibrosis (perifollicular fibrosis, dermal fibrosis)

9.   Presence or absence of mucin and it present whether dermal or perifollicular 

10. A PAS stain is helpful to evaluate fungal elements.