Wednesday, October 7, 2009

Is anyone assessing epidermal nerve fiber density in skin biopsies?

I recently received an advertising pamphlet from Therapath, a New York company offering to evaluate skin punch biopsy specimens in patients with suspected small fiber neuropathy. The pamphlet trumpets Therapath's proficiency, including "board certified neuropathologists meticulously reviewing cases". Although I have heard of this test, no clients of my practice have yet requested such a test. According to Therapath, the result is "reported as the average number of nerve fibers that cross the basement membrane at the dermal epidermal border, over a length of 1 mm. Making the correct diagnosis explains the symptoms, guides the evaluation for the underlying cause, and helps decide treatment". See the photomicrograph from Therapath's website of normal skin with small fibers (arrow) traversing the basement membrane (arrowhead) and coursing through the epidermis. Accompanying the pamphlet is a letter from "neuropathologist and laboratory director" William Harrington, MD in which he states that the American Academy of Neurology has added a practice guideline to include skin biopsy in the scope of practice when evaluating for polyneuropathies. He goes on to say that "skin biopsy for the determination of epidermal nerve fiber density is the most sensitive test for small fiber neuropathy". Therapath provides the clinician with a kit for biopsy collection and shipping to their facility at no extra charge. Eight to 12 days later, Therapath provides a full-color, quantitative laboratory report with images. If anyone has had experience with evaluating such biopsies, please comment on this post and provide us with your insights regarding the utility and technical requirements of this test. I'm not sure whether I would have to use a service such as Therapath's, or perform the service in-house. Thanks!

5 comments:

Brajesh said...

Recently, We sent a skin punch biopsy sample(performed by neurology faculty) to probably Johns Hopkins for suspected peripheral neuropathy. Meanwhile, we also got this advertisement from Therapath. We are considering skin biopsy more often. If it can be done in-house that will be excellent.

Craig said...

I've never heard of such an assay, nor have I heard of anyone either at U Pitt or here at U Kentucky requesting it. Would it be in conjunction with a sural nerve biopsy?

Brian E. Moore, MD said...

To Craig: I do not think that a sural nerve biopsy is routine with these skin biopsies.

To Brajesh:
I will look further into the issue and the technical requirements to see if we can get this up and running at our hospital. More posts to come on this issue at I find out more.

Cheryl said...

From my perspective as a patient, I was quite pleased that my physician recommended the epidermal nerve fiber biospy. The results clearly confirmed that I had small fiber neuropathy. The biospy is minimally invasive. My physician chose not to use the NY testing facility - he uses one in Florida.

Anonymous said...

Mass Gen does them in house they are a thick section free floating technique and Therapath often cites Mass Gen and Dr. Anne Louise Oaklander's work. Mass Gen is more precise in thei measurements.