What are the indications for a punch biopsy?
| | Fig. 51.1 Schematic demonstrating the technique for a shave biopsy of skin. (From Fewkes JL, Cheney ML, Pollack SV: Illustrated atlas of cutaneous surgery, New York, 1992, Gower Medical Publishing, with permission.) |
A punch biopsy may serve as an incisional or excisional skin biopsy, and is used to diagnose both inflammatory and neoplastic diseases. It provides a sample of tissue, which includes epidermis, dermis, and subcutaneous fat. When the pathology is thought to be localized to the epidermis and/or upper dermis, then a superficial shave biopsy may be more appropriate (Fig. 51-1). However, one should always try to completely remove pigmented lesions by conservative excisional or punch biopsy. When it is not possible to completely remove a pigmented lesion by excisional or punch biopsy, then the darkest and/or most elevated portion of the lesion should be biopsied, to achieve the highest diagnostic yield. It may also be prudent in these cases to take multiple “scouting” biopsies from different areas of concern within the lesion, to increase your chances of an accurate diagnosis and, in the case of a melanoma, to obtain an accurate Breslow depth. Punches range in size from 2 to 8 mm, with 3- or 4-mm punches being the most commonly used sizes. Disposable punches are especially useful for patients with hepatitis B or C, or HIV disease. |
