Procedures in Dermatology
Rich Callahan MSPA, PA-C
ICM I
Summer 2009
Overview
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Shave biopsy
Punch biopsy
Incision & Drainage (I&D)
Electrodessication & Curettage (ED&C)
Excisions
Cryotherapy
What is a skin biopsy?
• A skin biopsy is a diagnostic procedure in which a
portion of skin (and/or subcutis) is submitted to
the pathology lab.
• This specimen is fixed, sectioned and placed on
slides for histologic analysis
• Special stains can be used to detect fungus,
bacteria, immune complexes, lymphocytes,
inflammatory mediators, arthropods, etc.
• The hope is that the pathologist can provide more
information to aid in diagnosing the disease.
The biopsy is only as good as the
specimen you provide
• An inadequate specimen usually results in a
biopsy report including the dreaded words:
• “small quantity of tissue provided precludes
a definitive diagnosis.” or “superficial
representation of dermis in specimen
inadequate for full characterization of
disease process.”
Skin Biopsy
• A good skin biopsy is one that provides an
adequate specimen for the pathologist to review
while at the same time using the utmost care and
knowledge of anatomy to minimize the potential
morbidity of the procedure.
• Also involves post-biopsy wound care, knowledge
of anatomical danger zones, patient education.
Why do a skin biopsy?
• Skin biopsies usually provide diagnostic information that
adds to the clinical picture already at hand.
• Many skin diseases have characteristic findings on routine
histology that are highly diagnostic
• Biopsy results which support the clinical diagnosis tend to
confirm it.
• Biopsy results that don’t support the clinical diagnosis cast
it into doubt
• Biopsy results that don’t make sense at all should be
viewed with skepticism – (the lab makes mistakes too!)
• You might have to biopsy a lesion several times prior to
definitive diagnosis.
Why do a skin biopsy?
• Ascertain benign vs. malignant, infectious
vs. autoimmune, exogenous vs. endogenous
process, etc.
• If strongly suspect skin cancer, biopsy can
generate information such as subtype,
differentiation, depth of invasion, type of
spread, etc, which guides appropriate
choices for treatment
Keep in mind, skin biopsy not
necessary if….
• The clinical picture is entirely diagnostic.
• If patient history and PE findings strongly
point to a specific diagnosis, and you feel
comfortable in diagnosing on clinical
grounds alone, don’t do a skin biopsy.
• If the disease doesn’t respond to treatment
or doesn’t follow the expected clinical
course, then biopsy may be necessary.
Biopsy by shave technique
• Removal of representative piece of skin by
tangential incision with a blade.
• Can use scalpel or Dermablade
• I almost always use a Dermablade – basically a
sharp, thin, extremely flexible razor blade.
• Idea is to sample both lesional and normalappearing perilesional skin
• Depth needs to get down to at least superficial
upper dermis – biopsies of epidermis only usually
unsatisfactory. Some skin diseases require
sampling of mid to deep dermis for diagnosis.
When to do a shave
• Patient who isn’t as concerned with scarring
– by definition any defect which reaches
down to mid-dermis will scar.
• When you know it’s skin cancer – it’s going
to get removed anyway! Shave provides a
quick and accurate specimen and there will
be a scar from treatment anyway.
When to do a shave
• In sensitive anatomic locations where the
depth of a punch biopsy puts nerves/blood
vessels at risk (anatomic danger zones.)
• The highly active patient: Shave biopsy
wounds have no limitation on activity.
• The patient who can’t/doesn’t want to come
back for suture removal from punch biopsy.
How to do a shave
• Inform patient of potential for scarring!
• Anesthetize the area for biopsy, starting with the
subcutis and working you way up to the
dermoepidermal junction (bleb or peau d’orange.)
• Map in your mind or with a surgical pen the
specimen you are trying to collect beforehand (as
with many things in life/work, it helps to have a
plan first!)
• Create skin tension with hands or an assistant’s
hands.
How to do a shave
• Grasp blade between thumb and index finger,
place edge against skin and rotate hand in a gentle
back-and-forth motion which allows the blade to
saw through the tissue.
• Point the blade slightly downwards until you are
under the middle of your planned specimen, then
point slightly upwards until finished
• Goal is for a saucer-shaped specimen providing
adequate representation of the skin lesion.
Shave biopsy – Wound Care
• Resulting defect is usually a circular to ovular extending
down into papillary to mid-reticular dermis.
• Hemostasis with aluminum chloride/Monsel’s solution for
minimal bleeding/Electrocautery for moderate bleeding.
• After hemostasis achieved, ointment and occlusive
dressing are applied.
• Important that patient educated on keeping would moist
and occluded until healed.
• Wound bed is populated by granulation tissue and
fibroblasts 24-48 hours post procedure. These cells thrive
in a moist, low-oxygen environment!
• Scab formation greatly slows down the wound healing
process.
Biopsy by punch technique
• Removal of a representative piece of skin
and subcutis with a trephine, or punch
• Best way to look at it is like a little
cylindrical cookie-cutter which punches all
the way through the skin
• Usually a more involved procedure than
shave needing extra time for anesthesia,
hemostasis and would closure
When to do a punch
• Punch superior for any skin diseases where a
picture of the deep dermis/subcutis is diagnostic.
• Tends to provide more information for
inflammatory skin disorders, as they tend to
involve greater depth of dermis
• Usually a better choice for the scar-averse patient,
although it is no guarantee as even the best punch
biopsy closure can dehisce.
• Better choice for deeply-seated lesions in dermis
and subcutis.
How to do a punch
• Plan/map out the specimen you want
• Anesthetize the area, with particular care in
the subcutis and deep dermis.
• Carefully align the trephine with the skin,
and then gently push down/twist in one
direction. Gently pinch the skin around the
area with your free hand.
How to do a punch
• You will feel considerable resistance throughout
the dermis
• The trephine will then punch through to the
subcutis, which feels to the hand like a sudden
decrease in resistance to the trephine’s blade.
• Gently grab the specimen with pickups and lift it
out (a crushed specimen is an inferior specimen)
• Usually specimen lifts right out with small amount
of subcutis attached. If not, trim with scissors to
include small amount adherent fat.
How to do a punch
• Hemostasis then obtained with combination of
manual pressure, electrocautery or aluminum
chloride solution.
• Never forget: Pressure is the King of
Hemostasis!
• Wound then closed with sutures, or can be left to
heal by second intention (warn patient extended
wound care for 1-4 weeks in these cases)
Incision and Drainage (I&D)
• Treatment of choice for abscess, furuncle
and carbuncle – inflammatory collections of
pus and damaged tissue secondary to
infection
• Drainage of these lesions tends to lead to
quick resolution and provides material for
culture should specific antimicrobial
treatments become important
Incision and Drainage (I&D)
• Local anesthesia is obtained, and then a
moderate incision is made immediately
adjacent to the head, or “point” of the
lesion.
• Contents can occasionally be under
significant pressure!
• Majority of abscess contents then squeezed
out with bimanual pressure.
Incision and Drainage (I&D)
• Pus drainage/necrotic tissue can be collected for
culture
• Abscess can then be explored with a small curette
to free up any loculations and adherent debris
• Wound is then flushed several times with saline
solution.
• Wound left to heal by second intention
with/without sterile packing
Electrodessication and Curettage
(ED&C)
• Essentially a process whereby superficial
cancerous and pre-cancerous growths are
removed from the skin by repeated scraping
and burning.
• An effective, safe, expedient means of
treating certain skin cancers in certain
locations.
Electrodessication and Curettage
(ED&C)
• Indicated for SCC in situ, superficial and
selected nodular BCC.
• Works best on trunk and extremities in nonhairbearing areas
• Extreme caution on scalp, neck and highrisk areas of the face.
Electrodessication and Curettage
(ED&C)
• After appropriate regional anesthesia is obtained, a
curette is passed over the lesion with firm pressure
in back and forth strokes.
• Curettage is alternated with passes with
electrocautery for hemostasis.
• Technique is guided by feel – skin cancer yields
easily to the blade, whereas healthy dermis is quite
tough and leathery.
• When you reach firm dermis with regular pinpoint
bleeding, you are done.
Excision
• Procedure whereby a full thickness specimen of
skin is removed either for therapeutic or
diagnostic purposes.
• Excisions usually in elliptical shape oriented
along skin tension lines (Langer’s lines.)
• Can be left to heal by second intention or closed
by simple or intermediate repair.
• Procedure learned by seeing/doing. We will only
cover basic concepts here!
Why do an excision?
• Usually done to completely remove a lesion
for therapeutic reasons:
• Skin cancer
• Dysplastic nevus (abnormal mole)
• Epidermal inclusion cyst
Why do an excision?
• Can also be used for excisional biopsy, which is
when the larger, full-thickness specimen obtained
by excisional technique is needed for diagnostic
purposes.
• Example: Initial punch biopsy shows features
suggestive of CTCL (cutaneous T-cell lymphoma)
but pathology needs substantially more tissue for
gene rearrangement studies to further classify the
malignancy.
How to do an excision
• First of all, know what you are getting in
to.
• Excisions on the face, fingers, genitals out
of the scope of practice of most PA’s.
These regions have superficial blood
vessels, motor nerves, sensitive anatomical
features requiring advanced
training/familiarity to work with.
How to do an excision
• Scalp is richly vascularized – one can quickly get
into bleeding that is difficult to control
• Lower legs/feet – slowest healing parts of body
and also more prone to infection. Careful in the
elderly as concomitant diabetes/stasis disease can
predispose to complications such as poor healing,
wound infection and dehiscence.
How to do an Excision
• Plan your surgical margins and orientation of your
ellipse with skin tension lines
• Most excisions have elliptical shape to diminish
wound tension after closure
• Sterilize/Prep/Anesthetize skin and subcutis and
surrounding areas
• Cut specimen out in fusiform fashion holding
scalpel perpendicular to skin surface
• Blade is turned purely by rotation of blade handle
to keep its downwards track as vertical as possible
Surgical Excision
• After specimen is removed, hemostasis
achieved by pressure, electrocautery and
ligature – important to minimize chances of
hematoma formation, infection and necrosis
• Undermining of surrounding dermis may be
necessary to reduce wound tension, reduce
healing time, better cosmetic outcome and
minimize necrosis and/or wound dehiscence
Closure
• Simple Repair: Wound is closed with
single layer of top stitches: Non-absorbable
suture material tied in interrupted or running
fashion – penetrates both epidermis/dermis
• Intermediate repair: Wound closed with
buried layer of interrupted/ absorbable
sutures which encompass entire dermis and
up to dermoepidermal junction
Wound Care
• Minimize activity at least until top stitches
are out as more activity = more risk for fluid
accumulation, hematoma formation,
infection, wound dehiscence and gaping
scars
• Keep surface of wound moist and occluded
with petrolatum or polysporin/bacitracin
ointment and non-adherent wound dressings