Skin Biopsy

Indications

* Any skin lesion or eruption for which the diagnosis in unclear
* Any skin condition that has been unresponsive to therapy

Contraindication
* Any skin lesionthat is suspected to be a malignancy should be referred to a surgron for excisional biopsy rather than a punch biopsy


Materials

* 2-5 mm skin punch
* Minor proedure tray
* Curved iris scissors and fine toth forceps (ordinary forceps may distort a small biopsy specimen and should no be used)
* Specimen bottle containing 10% formalin
* Suturing materials (3-0 or 4-0 nylon)


Procedure

1. If more than one lesion is present, choose one that is well developed and repressentative of the dermatosis. For Patients with vesiculobullous disease, an early edematous lesion should be chosen rather than a vesicle. Avoid lesions that are excoriated or infected.

2. Mark the ares to be biopsied with a skin marking pen. Inject the lidocaine to from a skin wheal over the site of the biopsy.

3. After putting on sterile gloves and preparing a sterile field, perform the punch biopsy. First, immobilize the skin with the fingers of one hand, applying pressure perpendicular to the skin wrinkle lines with the skin punch. Core out a cylinder of skin by twirling the punch between the fingers of the other hand. As the punch enters the subcutaneous fat, resistance will lessen. At this point, the punch should be removed. the core of tissue usually pops up slightly and cut at the level of the subcutaneous fat with curved iris scissors without using forceps. If the tissue core does not pop up, it may be elevated by use of a hypodermic needle or fine-tooth torceps. Be sure to include a portion of subcutaneous fat in the specimen.

4. Place the specimen in the specimen container.

5. Hemostasis can be achieved by pressure with the gauze pad.

6. Defects from 1.5 and 2mm punches usally do not require suturing and will heal with very minimal scarring. Punch defects that are 2-4 mm can generally be closed with a single suture.

7. A dry dressing should be applied and removed the following day.

8. Sutures can be removed as early as 3 days from the face and 7-10 days from other areas.

Complications

* Infection (unusual)
* Hemorrhage (usally controlled by simple application of pressure)
* Keloid formation, especially in a patient with a prior of keloid formation.