Horizontal cross sectioning aids alopecia diagnosis

National report - As dermatologists and researchers gain more insight into the pathophysiology of non-scarring alopecia, Michael Ioffreda, M.D., emphasizes the importance of horizontal sectioning in the diagnosis of alopecia.

"The histology of alopecia has become its own specialty and one of the things that makes it different is the use of horizontal/transverse sectioning of the specimen. This type of processing and interpretation allows the dermatopathologist to look at every follicle in the specimen, enabling them to classify and count the follicles. In my opinion, this allows for a more accurate diagnosis of alopecia, especially when the clinical picture is subtle," says Dr. Ioffreda, who is associate professor of medicine (Dermatology) and Pathology at the Penn State Milton S. Hershey Medical Center College of Medicine.

Horizontal sectioning

"Horizontal sectioning has been used for some years. It was first described by Dr. Headington in 1984 and slowly caught on from there. So it is not new and was probably talked about more in the mid to late 90s as it became more popular, and now there is a group of dermatopathologists who advocate it for all alopecia biopsies. There are always people who are interested in learning this technique for the first time," Dr. Ioffreda says.

"Traditionally, specimens from the scalp have been cut using vertical sectioning. Imagine a cylinder or tube, standing it on one end, cut from top to bottom, that is typically what is done. With horizontal sectioning, the cylinder is laid flat and slices are made similar to cutting through a loaf of bread," Dr. Ioffreda tells Dermatology Times.

Dr. Ioffreda further discusses how some dermatopathologists do not like to use horizontal sectioning because they feel it does not provide an advantage. However, he believes that clinicians and researchers do gain a better understanding of the histopathology of alopecia with horizontal sectioning.

"The quantitative analysis of the biopsy is key. The method I like to use for grossing is to make one horizontal cut near the dermal-subcutaneous junction so as not to lose tissue from the more critical portions of the hair follicles," Dr. Ioffreda says.

Addressing diagnosis

Coming to a diagnosis is the first step in being able to treat alopecia properly. It allows the clinician to determine the course of treatment.

To obtain a proper histologic diagnosis, "First an overall assessment is done to determine if a normal number of hair follicles is present. If that is the case, then we can classify it as non-scarring, which means that the hairs have not been destroyed. Next, further sub-classification is done to determine whether the hairs are resting hairs or whether they are miniaturized. For instance, in hereditary balding, the hairs are getting smaller. They do not go away completely but turn to peach fuzz," Dr. Ioffreda says.

In making a histologic diagnosis, Dr. Ioffreda looks at whether the hairs are resting, actively growing and/or miniaturizing. He also looks at the pattern of inflammation, whether it is down deep in the fat around the lower part of the hairs or whether it is around the upper part of the hairs. Overall, the number of hair follicles, the state of hair growth and the pattern of inflammation aid in the diagnosis.

Practicing dermatologist

Dr. Ioffreda suggests that if a dermatologist would like to have this type of analysis done they should send their specimen to a dermatopathologist who specializes in horizontal sectioning and has experience in this type of analysis.

"Dermatologists should make sure their punch biopsy is 4 mm in size, as that is ideal and the recommended size. Most studies and published literature have utilized a 4 mm punch biopsy. With this size, you are also getting enough hair follicles to make a better quantitative assessment. When the dermatologist does the biopsy, the punch apparatus should be oriented parallel to the direction of hair growth, so as not to transect hairs with the biopsy procedure," Dr. Ioffreda says.