The Degree of Hair Follicle Miniaturization
My biopsy seems to be missing information on miniaturization
I’ve selected this question below for this week’s question of the week. It allows us to review some concepts regarding scalp biopsies.
Question
My scalp biopsy indicates that I have miniaturization and the pathologist felt that I have androgenetic alopecia. However, my report does not make any comment about the actual degree of miniaturization. Should it not provide this information? Is this not standard?
Answer
Normally a biopsy will show the number of terminal hairs and the number of vellus hairs. The ratio of the two gives the degree of miniaturization. A terminal to vellus ratio less than 4:1 suggests significant miniaturization is occurring. A terminal to vellus ratio above 5:1 suggests that there really is not much miniaturization.
It’s important to keep in mind that there are several ways that a biopsy specimen can be processed. It’s not always the same in every lab. One is called horizontal sections and one is called vertical sections. Horizontal sectioning gives a lot more information on hair numbers and it’s the only method whereby accurate estimates of miniaturization can be given. Miniaturization can be appreciated in biopsies processed with vertical sectioning but it can’t really quantify the degree of miniaturization. Just by the nature of how the biopsy is processed, vertical sections give 2-5 hairs and horizontal sectioning gives 20- 40.
All Scalp Biopsy Reports Are Not The Same
Not all pathologist gives the number of terminal and vellus hairs. Some just look at the slide and say “oh this is androgenetic alopecia” and then produce a generic report. Some pathologists even use “premade” templates whereby the look at a biopsy and then punch in a number so the computer spits out a generic report.
A pathologist who reads a lot of hair biopsies and has a significant interest in hair loss will often produce a detailed biopsy result including information related to:
1) The appearance of epidermis
2) Number of terminal and vellus hairs at various levels (i.e. T:V ratio)
3) Presence or absence of sebaceous glands
4) Presence of absence of inflammation and location of inflammation if present
5) Amount of perifollicular fibrosis, if present
6) Amount of dermal fibrosis, if present
7) Presence or absence of inflammation around blood vessels
8) Presence or absence of material in dermis such as mucin
Conclusion
No, not all biopsies will have information about the degree of miniaturization. If it’s a biopsy that was processed with ‘vertical’ sectioning it will simply not be possible to give this information to you. However, if the biopsy was processed with horizontal sectioning, the pathologist can obtain this information. however, whether he or she wants to spend the time to determine this information is a different story. It takes time to count the hairs in the biopsy and it takes time to produce a scalp biopsy report with all the features discussed above. Some don’t take this time.