Biopsy Techniques and Basic Excitions (Chapter 146)
Introduction
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INTRODUCTION
The cornerstone of dermatologic diagnosis is the correlation of clinical and histologic findings. A biopsy procedure is required in order to obtain tissue for pathologic examination, and fortunately the skin is more accessible than most other tissues. Modern instruments and techniques allow cutaneous biopsies to be performed efficiently with minimal tissue distortion. In some situations, a biopsy procedure is also curative, either coincidentally or intentionally. Knowledge of basic excisional surgical techniques can minimize cosmetic and functional impairment. Performance of a timely skin biopsy may also circumvent the need for more invasive procedures. Even critically ill patients can undergo a skin biopsy with minimal risk.
KEY CONCEPTS
Site Selection
Performance of a biopsy that will yield accurate and relevant histologic information depends upon the selection of an appropriate lesion or site within a lesion (Table 146.1).
The anticipated depth of the lesion to be biopsied must also be considered. In the case of a superficial lesion, e.g. an actinic keratosis versus Bowen disease, it can be assessed via a more "superficial" biopsy that extends to the papillary dermis. On the other hand, accurate diagnosis of a subcutaneous nodule, e.g. panniculitis versus polyarteritis nodosa, requires a biopsy that includes subcutaneous tissue.
Occasionally, fascia must be obtained, e.g. morphea profunda versus eosinophilic fasciitis. Disorders that primarily affect the collagen and elastic fibers within the dermis may have subtle histologic findings (e.g. atrophoderma of Pasini and Pierini) and longitudinally sectioned wedge biopsies that include both the affected area as well as adjacent normal-appearing skin prove most helpful.
The cornerstone of dermatologic diagnosis is the correlation of clinical and histologic findings. A biopsy procedure is required in order to obtain tissue for pathologic examination, and fortunately the skin is more accessible than most other tissues. Modern instruments and techniques allow cutaneous biopsies to be performed efficiently with minimal tissue distortion. In some situations, a biopsy procedure is also curative, either coincidentally or intentionally. Knowledge of basic excisional surgical techniques can minimize cosmetic and functional impairment. Performance of a timely skin biopsy may also circumvent the need for more invasive procedures. Even critically ill patients can undergo a skin biopsy with minimal risk.
KEY CONCEPTS
Site Selection
Performance of a biopsy that will yield accurate and relevant histologic information depends upon the selection of an appropriate lesion or site within a lesion (Table 146.1).
The anticipated depth of the lesion to be biopsied must also be considered. In the case of a superficial lesion, e.g. an actinic keratosis versus Bowen disease, it can be assessed via a more "superficial" biopsy that extends to the papillary dermis. On the other hand, accurate diagnosis of a subcutaneous nodule, e.g. panniculitis versus polyarteritis nodosa, requires a biopsy that includes subcutaneous tissue.
Occasionally, fascia must be obtained, e.g. morphea profunda versus eosinophilic fasciitis. Disorders that primarily affect the collagen and elastic fibers within the dermis may have subtle histologic findings (e.g. atrophoderma of Pasini and Pierini) and longitudinally sectioned wedge biopsies that include both the affected area as well as adjacent normal-appearing skin prove most helpful.
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