The skin is sampled with a small (34 mm diameter)tissue punch
. Lignocaine 1% is injected intradermallyfirst, and a cylinder of skin is incised with the punchby rotating it back and forth. Skin is liftedup carefully with a needle or forceps and the base iscut off at the level of subcutaneous fat. The defect iscauterized or repaired with a single suture. The biopsy specimen must not be crushed with the forceps orcritical histological patterns may be distorted.The tissue can be sent to the pathologist with asummary of the history, a differential diagnosis andthe patient's age. Close liaison with the pathologistis essential, because the diagnosis may only become apparent with knowledge of both the clinical and histological features.