Punch Biopsy of the Skin
May. 06, 2024
Punch Biopsy of the Skin
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Select the area for the biopsy, usually targeting the most abnormal-appearing region within a lesion or the edge of a rapidly growing lesion.
For more information, please visit Gastroscopy Biopsy Forceps and Punches.
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Cleanse the skin using a povidone-iodine solution followed by anesthesia administration with 2 percent lidocaine containing epinephrine. To minimize pain, use a 30-gauge needle for the anesthetic injection.
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Identify the lines of least skin tension for the biopsy site. For instance, on the arm, these lines run perpendicular to the limb’s long axis. The incision line should be parallel to the lines of least skin tension, which can be referred to from widely published diagrams if needed.
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Stretch the skin around the biopsy site using the thumb and index finger of the non-dominant hand (Figure 1). Stretch the skin perpendicular to the lines of least skin tension to ensure that once the skin relaxes after the procedure, an elliptical-shaped wound aligned with the tension lines is formed. On the arm, stretch along the limb’s long axis.
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Hold the punch biopsy tool vertically and rotate it downward with a twirling motion using the first two fingers of the dominant hand (Figure 2). Once it penetrates the dermis into the subcutaneous fat or reaches the hub, remove the instrument.
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Elevate the cylindrical skin specimen with the anesthesia needle held in the non-dominant hand. Avoid using forceps as they can cause crush artifacts. Use scissors in the dominant hand to cut the specimen from the subcutaneous tissues beneath the dermis level.
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Close the wound, if necessary, with one or two interrupted nylon sutures. Use 5–0 nylon for non-facial areas and 6–0 nylon for facial regions. Apply antibiotic ointment and a bandage after ensuring good hemostasis from the suture.
Innovative Applications of Skin Biopsy Punches in Dermatosurgery
The Keye's punch, with its rounded sharp cutting end and thick handle, is highly suitable for small skin biopsies. The thicker walls with angled sides above the cutting edge push tissue away, reducing dermis incision. To address this issue, thinner-walled disposable punches like the loo trephine have been developed.
The punch shaft is mounted onto a hand machine with adjustable rotational speeds ranging from 2000 to 10,000 rpm, available in various sizes from 0.5-1.3 mm.
Punch biopsies are straightforward, rarely cause complications, and small samples can heal without suturing. For non-facial lesions, a 4-mm punch is adequate, but for granulomatous or atypical conditions, biopsies of 5 mm or larger are preferable.
Modified Diagnostic Punch Techniques
Split-Punch Biopsy
This method involves obtaining two tissue samples from one punch biopsy by advancing the punch into the papillary dermis and then bisecting the specimen with a no. 11 blade. The punch is then reintroduced and extended to the subcutis, splitting the tissue.
Double-Trephine Punch Biopsy
Additional reading:5 Things to Know Before Buying Visual Trephines
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This technique is for obtaining tissue samples for diagnosing dermatoses affecting subcutaneous tissue. Initially, a 6-8 mm punch is used to remove the superficial core, followed by a 4 mm punch within the 8 mm defect for subcutaneous tissue.
String-of-Beads Biopsy
This involves performing smaller, adjacent 4 mm punch biopsies in a row. The individual defects can be closed in a linear or multiple O-to-Z/W design using nonabsorbable sutures with the simple interrupted suture technique.
The Pendulum or Scoop Biopsy
Shaving a flat lesion often results in insufficient depth for a representative sample. The scoop biopsy ensures adequate tissue sampling, providing a smooth edge for less trauma and faster healing without scarring. This method enhances prognostic accuracy for suspected malignancies. After cleansing and local anesthesia, counter traction is applied, and the punch tool scoops the skin like a pendulum.
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A 2 to 3 mm punch biopsy suffices for nail plate, nail bed, and nail matrix biopsies. For nail bed biopsies, the two-punch method uses a larger punch to remove the nail plate followed by a smaller punch to sample the bed.
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Skin punch as an adjunct to fine-needle aspiration (FNA) aids in diagnosing solid organ tumors close to the skin surface, such as lymph nodes, breasts, and thyroids, especially when FNA results are non-diagnostic.
Are you interested in learning more about Cervical Punch Biopsy Forceps Laparoscopy? Contact us today for an expert consultation!
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