Punch biopsy is an easy procedure which can be performed in the out-patient. 
This 74 year-old man was referred by his doctor because of a persistent swelling of the right lower lid with occasional bleeding. The appearance was suggestive of a basal cell carcinoma. He was listed for pentagon excision with primary closure. However, in order to obtain an accurate diagnosis before the surgery, a punch biopsy was performed in the clinic. 

If the histology confirmed basal cell carcinoma, then a 3 mm clear margin on either side would be necessary to ensure a complete excision. The resultant defect may then require cantholysis or Tenzel's flap to allow closure. However, a  benign histology means that pentagon excision without clear margin can be performed with direct closure. 

To perform a punch biopsy. The following instruments are needed: local anaesthetic (for example 1% lignocaine with adrenaline), punch biopsy needle, tooth forcep and cautery.
Step 1: infiltrate the skin with the local anaesthetic
Step 2: obtain the specimen by piercing the central lesion 
Step 3: use the tooth forcep to lift the specimen
Step 4: drop the specimen into a pot containing formaldehyde
Step 5: stop the bleeding with the cautery.