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Clinical Pearl: Deriving maximum information from skin biopsy specimens of inflammatory dermatoses
Pearls of wtsdom Clinical Pearl: Deriving maximum information from skin biopsy specimens of inflammatory dermatoses Clay J. Cockerell, MD Dallas, Texas Often when dealing with an inflammatory dermatosis, a clinician will submit a skin biopsy specimen to a dermatopathologist with the idea that the report will invariably lead to a specific diagnosis. For dermatopathologists, it is often frustrating to know that the clinician is anxiously awaiting the results of the interpretation when the histologic findings simply are not specific for any of the classically described inflammatory disorders. This is often because the histologic findings described in textbooks of dermatopathology are derived from tissue sections taken from typical cases. Dermatologists are often consulted on cases that have already been evaluated by primary care physicians or have been previously treated by one or more medications. Rarely will a dermatologist submit a typical case of psoriasis or lichen planus to biopsy because such disorders are so readily apparent clinically that no further information is needed to render a correct diagnosis. Thus we are taught to recognize typical examples histologically, but we are confronted almost exclusively with unusual cases. Nevertheless, the skin biopsy specimen remains pivotal in the evaluation of inflammatory skin disorders and in many instances may be definitive. In that the dermatopathologist is operating somewhat at a disadvantage at the outset, it is important that clinicians know how to optimize the results that may be obtained from the biopsy specimens. The following are suggestions on ways in which information gleaned from a biopsy specimen taken from an inflammatory dermatosis can be maximized to lead to more accurate diagnoses and more effective therapy. 1. Have the patient discontinue taking any inflammation-suppressant medication before performing the biopsy. Topical as well as systemic corticosteroids lessen the amount of inflammation in JAM ACAD DERMATOL 1994;30:116·7. Copyright @ 1994 by the American Academy of Dermatology, Inc. 0190-9622/94 $1.00
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skin lesions, thereby altering characteristic histologic patterns that are used in diagnosis. The longer the patient can tolerate withdrawal from the medication before the biopsy the better. This can be difficult for both the physician and the patient, but sometimes it is necessary to determine exactly what is going on histologically. 2. Take more than one specimen from lesions at different sites. Some diseases appear completely different microscopically in different body sites so that it is often important to sample several different areas. Inflammatory disorders on the elbows, knees, and over the knuckles commonly have an unusual appearance, so it isrecommended that these areas be avoided, if possible, or, if they are sampled, take specimens from other areas as well. 3. Take more than one sample from lesions at different stages in evolution.Diseases vary greatly in their histologic appearances depending on when in the course of the illness the specimen is obtained. Early evolving and late resolving lesions may show only nondescript changes so that specimens should be taken from fully developed lesions whenever possible. On the other hand, it may be helpful to demonstrate the range of histologic-features that may be observed in a given disease as in discoid lupus erythematosus in which thickening of the basement membrane and epidermal thinning, two helpful findings, are often visible only in long-standing lesions. 4. Sample intact lesions. Lesions that have been scratched or otherwise traumatized may be altered in ways that obscure typical histologic findings. Furthermore, impetiginized lesions may demonstrate artifactual atypical cytologic features or may obscure classic histologic patterns. 5. Describe the condition thoroughly. Although it may he acceptable to write simply "rule out wart" or "keratosis" when sampling lesions that are generally characteristic, when dealing with an inflammatory skin condition, it is important to provide the
Journal of the American Academy of Dermatology Volume 30, Number I
pathologist with as much clinical information as possible. Dermatologic diagnoses are based on clinicopathologic correlation; providing the pathologist with sketchy, misleading, or no information diminishes this correlation and lessens the possibility of a complete and accurate diagnosis. Some clinicians submit the same clinical diagnosis in virtually every case for purposes of convenience. This also lessens the ability to perform clinicopathologic correlation. Some disorders may have a virtually identical histologic appearance (e.g., lichen planus-like keratosis and lichen planus) so that in the absence of a clinical description, an accurate diagnosis often cannot be rendered. In some cases, it may be helpful to provide a clinical photograph or to arrange to have the dermatopathologist view the patient at a conference or in consultation, especially if the dermatopathologist is trained in clinical dermatology. It is also always helpful to discuss difficult cases with the pathologist who may ask pertinent questions or make suggestions that might lead to an accurate diagnosis. 6. Submit specimens to a board-certified dermatopathologist. Although this might sound like a "plug," dermatologic diagnoses, especially in the case of inflammatory dermatoses, depend heavily on clinicopathologic correlation. Despite what might be excellent training otherwise, without exposure to clinical dermatology, general surgical pathologists often simply cannot correlate histologic findings with clinical ones. This often results in specimens having to be submitted for consultation with increased cost and delay in diagnosis. 7. Review your own biopsy specimens. This is especially important if you do not have access to a board-certified dermatopathologist in which case you will almost certainly have far more expertise in clinical dermatology than your pathologist colleague. By examining your own specimens, you develop more experience in dermatopathology and maintain an appreciation for the problems that your pathologist encounters.
Pearls of wisdom 117 8. Perform generous, technically excellent biopsies. Although we pathologists often get a bad reputation for seemingly always "wanting more tissue," the general rule applies that the more tissue available for review, the greater the amount of information that can be garnered. A distinction must be made between specimens taken primarily for cosmesis and those taken for diagnostic purposes. Obviously, no pathologist would recommend an excisional biopsy of a small lesion on the nose of a young person. N evertheless, we often receive superficial shave biopsy specimens of inflammatory disorders including suspected alopecias and panniculitides! Punch and incisional biopsy specimens are recommended for virtually all inflammatory skin conditions although deep shave or saucerization specimens may be adequate in some cases such as subepidermal blistering disorders. Small punch biopsy specimens such as 2 and 2.5 mm provide only limited information and larger punches, such as those 4, 5, and 6 mm are recommended whenever possible. 9. Handle the tissue with care. Once the biopsy has been performed, it is important that the tissue be handled properly. Aggressive squeezing with forceps or "spearing" with a needle often results in extensive crush artifact that can render even the best of specimens completely uninterpretable. Tissue that is not placed promptly in the appropriate fixative or transport medium undergoes autolysis that also alters histologic features. It is also essential that the clinician be certain that the biopsy specimen actually enters the fixative as punch specimens may remain in the punch itself and shave specimens may remain on the surface of the scalpel or razor blade. Once tissue is placed in the bottle, it is important to ensure that it is not adherent to the side of the bottle or becomes crushed in the lid. Although dermatopathologists often render diagnoses that are simply "descriptive," by following some of these guidelines, the amount of information derived from biopsy specimens can be maximized to the benefit of your patients.
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skin lesions, thereby altering characteristic histologic patterns that are used in diagnosis. The longer the patient can tolerate withdrawal from the medication before the biopsy the better. This can be difficult for both the physician and the patient, but sometimes it is necessary to determine exactly what is going on histologically. 2. Take more than one specimen from lesions at different sites. Some diseases appear completely different microscopically in different body sites so that it is often important to sample several different areas. Inflammatory disorders on the elbows, knees, and over the knuckles commonly have an unusual appearance, so it isrecommended that these areas be avoided, if possible, or, if they are sampled, take specimens from other areas as well. 3. Take more than one sample from lesions at different stages in evolution.Diseases vary greatly in their histologic appearances depending on when in the course of the illness the specimen is obtained. Early evolving and late resolving lesions may show only nondescript changes so that specimens should be taken from fully developed lesions whenever possible. On the other hand, it may be helpful to demonstrate the range of histologic-features that may be observed in a given disease as in discoid lupus erythematosus in which thickening of the basement membrane and epidermal thinning, two helpful findings, are often visible only in long-standing lesions. 4. Sample intact lesions. Lesions that have been scratched or otherwise traumatized may be altered in ways that obscure typical histologic findings. Furthermore, impetiginized lesions may demonstrate artifactual atypical cytologic features or may obscure classic histologic patterns. 5. Describe the condition thoroughly. Although it may he acceptable to write simply "rule out wart" or "keratosis" when sampling lesions that are generally characteristic, when dealing with an inflammatory skin condition, it is important to provide the
Journal of the American Academy of Dermatology Volume 30, Number I
pathologist with as much clinical information as possible. Dermatologic diagnoses are based on clinicopathologic correlation; providing the pathologist with sketchy, misleading, or no information diminishes this correlation and lessens the possibility of a complete and accurate diagnosis. Some clinicians submit the same clinical diagnosis in virtually every case for purposes of convenience. This also lessens the ability to perform clinicopathologic correlation. Some disorders may have a virtually identical histologic appearance (e.g., lichen planus-like keratosis and lichen planus) so that in the absence of a clinical description, an accurate diagnosis often cannot be rendered. In some cases, it may be helpful to provide a clinical photograph or to arrange to have the dermatopathologist view the patient at a conference or in consultation, especially if the dermatopathologist is trained in clinical dermatology. It is also always helpful to discuss difficult cases with the pathologist who may ask pertinent questions or make suggestions that might lead to an accurate diagnosis. 6. Submit specimens to a board-certified dermatopathologist. Although this might sound like a "plug," dermatologic diagnoses, especially in the case of inflammatory dermatoses, depend heavily on clinicopathologic correlation. Despite what might be excellent training otherwise, without exposure to clinical dermatology, general surgical pathologists often simply cannot correlate histologic findings with clinical ones. This often results in specimens having to be submitted for consultation with increased cost and delay in diagnosis. 7. Review your own biopsy specimens. This is especially important if you do not have access to a board-certified dermatopathologist in which case you will almost certainly have far more expertise in clinical dermatology than your pathologist colleague. By examining your own specimens, you develop more experience in dermatopathology and maintain an appreciation for the problems that your pathologist encounters.
Pearls of wisdom 117 8. Perform generous, technically excellent biopsies. Although we pathologists often get a bad reputation for seemingly always "wanting more tissue," the general rule applies that the more tissue available for review, the greater the amount of information that can be garnered. A distinction must be made between specimens taken primarily for cosmesis and those taken for diagnostic purposes. Obviously, no pathologist would recommend an excisional biopsy of a small lesion on the nose of a young person. N evertheless, we often receive superficial shave biopsy specimens of inflammatory disorders including suspected alopecias and panniculitides! Punch and incisional biopsy specimens are recommended for virtually all inflammatory skin conditions although deep shave or saucerization specimens may be adequate in some cases such as subepidermal blistering disorders. Small punch biopsy specimens such as 2 and 2.5 mm provide only limited information and larger punches, such as those 4, 5, and 6 mm are recommended whenever possible. 9. Handle the tissue with care. Once the biopsy has been performed, it is important that the tissue be handled properly. Aggressive squeezing with forceps or "spearing" with a needle often results in extensive crush artifact that can render even the best of specimens completely uninterpretable. Tissue that is not placed promptly in the appropriate fixative or transport medium undergoes autolysis that also alters histologic features. It is also essential that the clinician be certain that the biopsy specimen actually enters the fixative as punch specimens may remain in the punch itself and shave specimens may remain on the surface of the scalpel or razor blade. Once tissue is placed in the bottle, it is important to ensure that it is not adherent to the side of the bottle or becomes crushed in the lid. Although dermatopathologists often render diagnoses that are simply "descriptive," by following some of these guidelines, the amount of information derived from biopsy specimens can be maximized to the benefit of your patients.