What kind of things do you look for in a biopsy report that tells you it was a good biopsy report?
Thanks for the great question. This is a topic we don’t touch upon all that often and so I’m glad you’ve brought it to attention. Let me begin by saying that biopsies are important for some complex cases of hair loss. They are not needed in every patient. Biopsies can be extremely useful if done properly. They can also be extremely misleading if certain pieces of information are left out. Here are some of the top 10 things I look for when reading a report.
TOP 10 FEATURES OF A BIOPSY REPORT
1. SIZE OF THE BIOPSY SHOULD 4 mm
A punch biopsy is deal and should be 4 mm in size. Too often smaller punches (3 or 2 mm) are used in attempt to limit scars for the patient. While this is a good thought, smaller biopsied provided limited information.
2. THE PATHOLOGIST SHOULD COMMENT ON THE DEPTH OF THE BIOPSY
Ideally, it’s nice to see that the biopsy goes deep enough into the scalp so that the pathologist has a good chance to see what’s happening at the very bottom of the hair follicles and even into the fat. Conditions like alopecia areata and many autoimmune and inflammatory conditions and scarring alopecias (dissecting cellulitis) go quite deep. A biopsy must be deep enough to capture. this.
Many biopsies are not deep enough. Sometimes, there’s just too much bleeding during the biopsy and a physician is afraid to go deeper. Sometimes the punch technique the physician is using is not adequate and the punch is simply not pushed deep enough when taking the sample.
3. HORIZONTAL SECTIONING OF THE BIOPSY SAMPLE WAS CONSIDERED.
A biopsy specimen can be cut side to side (horizontal sections) or up and down (vertical sections). Many labs nowadays will do both. It’s nice to have horizontal sections as this gives the pathologist a lot of information on 12-30 hair follicles. Vertical sections give information on 3-7 hair follicles. I prefer to work with a pathologist who reads horizontal sections as it gives a great deal more information. Most labs perform horizontal sections.
4. THE PATHOLOGIST COMMENTS ON THE PROPORTION OF TERMINAL HAIRS, VELLUS HAIRS, ANAGEN HAIRS AND TELOGEN HAIRS IS GIVEN.
If horizontal sections are used to process the sample, it’s important to know exactly what the pathologist sees. In this regard it’s nice to have information about the proportion of terminal hairs, vellus hairs, anagen hairs and telogen hairs in the biopsy.
1) A high proportion of vellus hairs relative to terminal hairs given a clue to possible androgenetic alopecia. Horizontal sections allow the pathologist to comment on the ratio of terminal hairs to vellus hairs - which is a wonderful clue for diagnosing andrognetic alopecia and in some cases also chronic telogen effluvium. A terminal to vellus ratio less than 4:1 means androgneetic alopecia in most cases and a T:V ratio above 8:1 signifies chronic TE.
2) A high proportion of telogen hairs may also offer information about possible underlying telogen effluvium. For example, normally there are less than 12 % telogen hairs in a biopsy. As the percent of telogen hairs rises above 12-15 % one must also wonder if a telogen effluvium is present. The diagnosis of telogen effluvium is more of a clinical diagnosis than a pathology diagnosis. So, even if the percentage of telogen hairs is less than 12 %, it’s still posisble that a patient has a telogen effluvium.
5. THE PATHOLOGIST COMMENTS ON THE SEBACEOUS GLAND (OIL GLAND) DENSITY
When I read a report, I want to know what’s happening to the sebaceous glands (oil glands). This is often surprising to hear as one would normally imagine one would like to know what’s happening to the hair follicles themselves. I certainly do want to know what’s happening to the hair follicles (see below), but I’d like to know if the sebaceous glands are present, if they appear bigger in the biopsy or if they are reduced. Reduction in the density of sebaceous glands is very much a feature of scarring alopecias. A relative increase in the appearance of sebaceous glands is a feature of many non scarring alopecias such as androgenetic alopecia. This information is sometimes left out of reports and it’s so incredibly helpful to have.
6. THE PATHOLOGIST COMMENTS ON THE PRESENCE OR ABSENCE OF SCAR TISSUE (FIBROSIS)
It’s important to know if there is scar tissue present in the skin. Scar tissue is often referred to as fibrosis, and it’s nice to know if there is scarring around the hairs (perifollicular fibrosis) or more widespread in the skin (interfollicular fibrosis).
This is perhaps the most easily confused part of interpreting biopsies since perifolliclar fibrosis can be seen in both non scarring as well as scarring alopecias. It’s easy to over interpret the presence of perifollicular fibrosis as indicating a scarring alopecia.
For example, perifollicular fibrosis is seen in many biopsies from the non scarring hair loss condition known as androgneetic alopecia (male balding). However, the tip off that a biopsy from a patient with male balding is not a scarring alopecia is the fact that the sebaceous glands are still present and there is no lichenoid inflammation (see below). In lichen planopilaris (one of the scarring alopecias), there is perifollicular fibrosis, lichenoid change and reduction in sebaceous glands.
7. THE PATHOLOGIST COMMENTS ON THE PRESENCE OR ABSENCE OF INFLAMMATION.
Most biopsies have bits of inflammation here and there (sparse inflammation) and some have more Inflammation. When inflammation is present, it’s nice to know whether the pathologist feels it’s mild, moderate or severe. In addition, it’s important to know where the inflammation is found. Is it up high in the skin… or is it in the middle or is it down low at the level of the bulb. In scarring alopecias and androgenetic alopecia, the inflammation is high up in the level of the so called isthmus (fairly close to the skin level). In alopecia areata, the inflammation is quite deep in the skin around the hair follicle bulb.
I also look for the type of inflammation. Most inflammation in biopsies is comprised of a type of white blood cell called lymphocytes. But the presence of other inflammatory cells like lymphocytes, neutrophils or plasma cells might mean different things in different situations.
8. THE PATHOLOGIST COMMENTS ON CELL DEATH
If hair follicle cells in the biopsy are dying this is important. There are two mains ways that cells die - apoptosis and necrosis. These is a specific pattern of cell death in scarring alopecias called “lichenoid inflammation” that gives death of hair follicle keratinocytes. The presence of lichenoid inflammation in a biopsy really points towards a diagnosis of certain scarring alopecias such as lichen planopilaris or frontal fibrosing alopecia. . This information on cell death is desperately needed but too often left out of reports.
9. THE PATHOLOGIST COMMENTS ON WHAT’S HAPPENING ELSEWHERE IN THE BIOPSY
It’s nice to know the biopsy was looked at carefully. Ideally a report should comment on the presence of inflammation in other parts of the biopsy - not only around the hair follicle. This would include the presence of inflammation around blood vessels (called perivascular inflammation) and the presence of inflammation around other gland structures (like eccrine glands). In addition, some biopsies show that the body has produced and left behind extra material in the skin (like mucin for example). All this information is very helpful to know about.
10. THE PATHOLOGIST DECIDES IF ANY SPECIAL STAINS WERE NEEDED AND COMMENTS ON THESE FINDINGS
A variety of special ‘stains’ are available in the world of pathology. These stains are used to help identify specific substances in the skin or specific markers on cells. Special stains are commonly used to identify fungi (PAS stain). Other stains like gram stain may be used for identifying the presence of bacteria. An Alcian blue stain is commonly used to identify a substance in the biopsy known as mucin which may point to come autoimmune processes. Elastic stains are used to identify patterns of scarring.
I don’t usually need a biopsy to make a diagnosis. But if I’m going to do a biopsy, I want the pathology report that comes back to be a good one. I want it to be useful to my patient. I want the report to contain all the features that allows be to be as close to 100 % confident as to what’s going on in the scalp of the patient.