July 31, 2010

| perri dermatology
Medically reviewed by Anthony J. Perri, M.D.

A punch biopsy involves removing the full thickness of the skin (epidermis, dermis, and fat) in a defined area.  Punch biopsies range in size from 2mm – 1 cm and are circular in shape.  Essentially, they allow the removal of a skin lesion smaller than the diameter of the punch biopsy and can be used anywhere on the body.  The depth can be adjusted to sample just the dermis or deeper into the fat depending on how deep the dermatologist inserts it into the skin.  These biopsies are preferred for the removal of very small moles that can be completely encompassed within the punch biopsy.  A circular defect is left in the skin after a punch biopsy, which is quickly and painlessly closed with one to two sutures.  Punch biopsies are also very useful for the biopsy of a rash, which typically involves all three layers of skin.  The dermatopathologist is able to assess the rash by evaluating all of these layers under the microscope.