2013 Antech Diagnostics. All rights reserved. March/April 2013 Focus: Dermatopathology. Skin biopsy do s & don ts

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1 News, Advice and Research from ANTECH Diagnostics ANTECHINSIGHTS March/April 2013 Focus: Dermatopathology Get familiar with ANTECH s DermPath consult service Dual review by boarded specialists offers advantages Skin biopsy do s & don ts Improve your diagnostic yield with 5 simple rules! Make the most of your DermPath consult Three essential steps for a rewarding result Journal update: Risk factor for MRSP discovered Highlights from recent JAVMA article by JS Weese et al. Get familiar with ANTECH s DermPath consult service Dual review by boarded specialists offers advantages over pathology alone Jeffrey Edwards, DVM, MPH, DACVP, Chief, Anatomic Pathology, ANTECH What s a DermPath consult? ANTECH s Dermatopathology consulting service provides diagnosis of skin diseases and, if possible, treatment recommendations for your patient. Our DermPath service couples the expertise of board-certified dermatologists and board-certified pathologists with dermatopathology specialization. The goal? To deliver a higher level of analysis of skin biopsy specimens and more complete diagnostic and treatment recommendations than is possible with pathology alone. How does it work? To order a DermPath consult (Test Code: DERM), submit specimens in formalin as usual, accompanied by the ANTECH DermPath consultation form, along with relevant photos and labwork if possible. 1

2 An ANTECH board-certified pathologist first reviews the slides to make a morphologic diagnosis, and if possible, an etiologic diagnosis. The pathologist s interpretation along with the submission report and sections of the biopsies are then sent to the dermatologist for assessment. The dermatologist reviews the clinical history, images and histopathology to provide diagnostic and treatment recommendations. We ve got one of the deepest benches in the industry. With a combined 12 dermatologists and pathologists specializing in dermatopathology on board, ANTECH s DermPath consult team collectively represents 235 years post-dvm experience, or 20 years on average per team member. ANTECH DermPath Consultation Team Dermatopathologists: Pamela Luther, DVM, DACVP Derick Whitley, DVM, DACVP James Tappe, DVM, PhD, DACVP Marlan R Fender, DVM, MS, DACVP Kai-Ning Tang, DVM, MS, PhD, DACVP Erin Locke, DVM, DACVP Dermatologists: Dr. Joseph A. Bernstein, DVM, DACVD Linda Messinger, DVM, DACVD Deirdre Vaughan, MS, DVM, DACVD Lori Thompson, DVM, DACVD Stephen L. Lemarie, MS, DVM, DACVD Chris Reeder, DVM, DACVD 2

3 I invite you to learn more about ANTECH s DermPath consultation team by perusing our brief team bios. You ll be impressed by what you find. Please don t hesitate to call the ANTECH Consult Line or contact me personally at jeffrey.edwards@antechmail.com if you have questions about our DermPath consult service. Practical Tips: Skin biopsy do s & don ts Improve your diagnostic yield with 5 simple rules! Pamela Luther, DVM, DACVP Skin conditions in animals are particularly challenging to deal with in everyday practice. Skin conditions with varying etiologies often present with very similar clinical signs and and getting to the bottom of the etiology for any particular patient can require considerable time and diagnostic testing. What enables our pathologists to do an excellent job for you? A good history and good samples. Here are five golden rules to providing good skin biopsies, along with some important exceptions to the rules to be aware of! Skin biopsies done early in the process, when lesions are new and/or fresh, can avoid the problems of non-specific changes due to chronicity or secondary bacterial infection, and provide a more definitive primary differential list, along with a faster resolution to the problem. From the standpoint of histopathology, 4 mm punch biopsies are almost useless, even if there are several, as they are difficult to embed and cut properly. They also include too few hair follicles for evaluation of hair follicle growth in cases of alopecia. 6mm biopsies are good, 8mm biopsies are better, and wedges are even better. Whenever possible, submit multiple specimens from different stages of the disease. Try to include subcutaneous tissue (fat) if possible. From a billing standpoint, unlike submitting multiple biopsies from different lesions such as tumors, which are billed as individual specimens, multiple specimens from dermatologic conditions are counted as one tissue! So you will not incur additional charges for sending 10 biopsies rather than a single biopsy. Please do not scrub the patient s skin prior to biopsy! Remember the diagnosis is often in the stratum corneum or surface crust. For some reason, many general practitioners have been taught to biopsy at the margin of lesions. As a general rule, you should biopsy the middle of the lesion at multiple sites and various stages of development. In cases where alopecia is a significant component, try to biopsy in the areas of most obvious hair loss and avoid less affected areas and the margins of affected areas. 3

4 Exceptions to the rule: 2013 Antech Diagnostics. All rights reserved. Ulcerated lesions. Biopsy at the margin so we can see the development of the ulcer as well as changes in the intact epithelium. Nodular or deep lesions. A wedge or excisional sample is best for nodular lesions or deep lesions involving subcutaneous fat. If wedge/excisional samples are not possible, biopsy the middle of the lesion and be sure to include the deep subcutaneous tissue. A common mistake it to take biopsies while the patient is on corticosteroids or when corticosteroids have only recently been withdrawn. Corticosteroids reduce or change the type of inflammation we see in biopsy specimens, which can be misleading from a diagnostic standpoint. They can also mislead the pathologist by altering follicular growth and mimicking the changes seen in endocrine dysfunctions. In contrast, taking biopsies while patients are on antibiotic therapy is actually a good idea, since that generally avoids changes associated with secondary infections. In conclusion, the better your skin biopsies, the more likely we can analyze your samples without delay or follow up. And remember: no matter how excellent your biopsies are, they have little value without an equally excellent patient history, as outlined in Dr. Bernstein s article in this issue. From Our Experts Make the most of your DermPath consult Three essential steps for a rewarding result Joseph A. Bernstein, DVM, Diplomate ACVD Like most collaborations with outside specialists, the most satisfactory DermPath consult is achieved when both the input (your case submission) and the output (our analysis and recommendations) are complete and high quality. How do you ensure your DermPath submission is up to par? Here are three essential steps to ensure you get the most information from your dermatopathology consultation: Step 1: Reality check - does it make sense to biopsy this case? One of the most frequent causes of non-diagnostic biopsy samples is inappropriate case selection. The classic example is biopsy of a chronic allergic patient or a patient with recurrent Staph pyoderma or Malassezia yeast overgrowth. Biopsies of chronic hypersensitivity reactions or allergic patients with recurrent secondary infections do not help with identifying the underlying etiology. The histopathology from patients with parasite hypersensitivity (i.e., flea allergy, scabies), food allergy, and atopy from environmental allergies all look the same on histopathology. The histopathology will invariably have a generic mixed inflammatory infiltrate that may or may not have evidence of overlying secondary infection. Clinical differentiation of these diseases is required, and assessment of secondary infections is more efficiently performed with cytology. Biopsies of pruritic animals are appropriate when the clinician has differential diagnoses that are not related to allergy. Step 2: Optimize your biopsy site selection and timing. Common reasons for non-diagnostic biopsy specimens include inappropriate sample selection and timing of the biopsies. It is essential to biopsy multiple representative primary lesions when trying to make 4

5 a diagnosis by histopathology. For example, if a patient has a waxing-waning disease and biopsies are taken while the disease is in a quiescent phase, this will result in non-diagnosis. Maximizing your results requires taking representative samples of adequate size and number while the disease is in an active flare. A classic example of this is occurs with cases of Pemphigus foliaceous (PF). The primary lesions of PF are pustules with acantholysis (loss of cohesion between epidermal cells). If intact pustules are not sampled during an active flare of the disease, the biopsy specimens will not demonstrate the key features and will appear no different than allergic disease with secondary pyoderma. Please see Dr. Luther s article, Skin Biopsy Do s & Don ts for other practical tips. Step 3: Use the DermPath consult form and provide a complete case history. ANTECH s DermPath consult form offers a straightforward template for high quality case submissions. And remember -- dermatology is a visual science. Include photos if possible! The essential information we need includes: Signalment and history. Our specialists cannot deduce what a histologic presentation means without history. For example, a single histiocytic mass in a young dog would most likely be a histiocytoma, while similar histopathology in a dog with a history of multiple masses might be reactive histiocytosis or a granulomatous infectious disease. It is critical that you include: Complete signalment including species, breed, age, gender and coat color; Duration of the skin disease as well as the nature of onset (acute vs slowly progressive); The patient s indoor/outdoor status and exposure to other animals; If the patient is itchy, the degree and nature of the pruritus is important. Is the pruritus seasonal or nonseasonal? Are there people or animals in contact with the patient that also are pruritic or have dermatologic disease? How long has the condition been present? If the disease has been long-standing, has the appearance changed over time? Clinical description. In addition to an accurate description of the patient s clinical signs, we need to know the following from your physical examination: Anatomic distribution/localization of lesions - Is the disease focal, multi-focal, or generalized? Certain diseases target specific areas of the body so assessment of the list of differential diagnoses is changed based on the distribution. Types of primary and secondary lesions - Are there pustules, papules, plaques, masses, or erythema? Are there ulcers, excoriations, erosion and crusts? If there is alopecia, is the alopecia partial or complete? Is hair loss associated with inflammation or do the alopecic areas of skin appear normal? Submission of high resolution images with the biopsies makes this job easier. These can be submitted on a CD or printed for inclusion with the DermPath submission. Diagnostic test results. Remember to include previous results, including skin scrapings, surface cytology, DTM, bacterial cultures, and/or bloodwork. Dermatologists usually recommend that baseline diagnostics (skin scrapes, cytology, DTM) be performed prior to biopsies. If these have not been done, we will commonly recommend that they be performed as biopsies are poorly sensitive for mites, dermatophytes and superficial infections. Doing a biopsy without performing baseline diagnostics can result in non-diagnostic biopsies (i.e., yeast and Staph infections) or unnecessary biopsies (i.e., Demodex infestation). 5

6 Treatments and response. What have you done therapeutically in the past and how has the patient responded? Be sure to include: antibiotics, antifungals, steroids, topicals, parasiticides and dietary trials. If you have treated, for how long and what was the response? Again, your bases will be covered if you employ the ANTECH DermPath consult form, which can be copied and used for each patient submission. The reward of completing all 3 steps for higher-quality case submissions? More efficient and predictable turnaround times for your DermPath consults, and more targeted, complete and accurate analysis and recommendations by our specialists. For further information about ANTECH s DermPath consult service, please contact the ANTECH consult line. Journal update: Risk factor for MRSP discovered Highlights from recent JAVMA article by Weese et al. The prevalence of methicillin-resistant Staphylococcus infections continues to grow in both general and specialty small animal practices across the country. The frequency of methicillin resistance in Staphylococcus pseudintermedius the most common species of Staphylococcus found in pets increased approximately 80% just between 2008 and 2011 in an analysis of nearly 100,000 samples cultured by ANTECH. A recent study by Weese et al. published in JAVMA found a significant association between recent (prior 30 days) antibiotic administration and methicillin-resistant Staphylococcus pseudintermedius (MRSP) infection in dogs. This is not surprising, because the use of antibiotics provides selection pressure favoring methicillin-resistant organisms. Although there is no evidence that MRSP is more pathogenic than MSSP, the rapid emergence of MRSP is of concern because the greater difficulty in treating infections caused by MRSP and the impact of MRSA in human medicine. Common conditions for which antibiotics may be prescribed but are not indicated: Veterinarians can help mitigate the rise in prevalence of methicillin resistance by avoiding inappropriate use of antimicrobials, and carefully selecting drugs, dose, and treatment duration when antibiotics are indicated. Prudent antimicrobial use is an important measure all practitioners can strive towards to help reduce the growing prevalence and impact of this pathogen. Reference: JS Weese, MC Faires, LA Frank, LM Reynolds, A Battisti, Factors associated with methicillin-resistant versus methicillin-susceptibel Staphylococcus pseudintermedius infection in dogs, JAVMA 2012;240: Elevated WBC count with no other indication of bacterial infection. Elevated liver enzymes with no other indication of bacterial infection. Young cats with lower urinary tract disease due to idiopathic cystitis Kittens and puppies with viral upper respiratory tract disease Borrelia burgdorferi infections without clinical signs of Lyme disease. 6