A procedure in which a small round piece of tissue about the size of a pencil eraser is removed using a sharp, hollow, circular instrument. The tissue is then checked under a microscope for signs of disease. A punch biopsy may be used to check for certain types of cancer, includingskin, vulvar, and cervical cancer. It may also be used to check for certain skin conditions and changes that may lead to cancer. Punch biopsy. A hollow, circular scalpel is used to cut into a lesion on the skin. The instrument is turned clockwise and counterclockwise to cut down about 4 millimeters (mm) to the layer of fatty tissue below the dermis. A small sample of tissue is removed to be checked under a microscope. Skin thickness is different on different parts of the body.