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Skin biopsy is a
biopsy A biopsy is a medical test commonly performed by a surgeon, interventional radiologist, or an interventional cardiologist. The process involves extraction of sample cells or tissues for examination to determine the presence or extent of a disea ...
technique in which a
skin lesion A skin condition, also known as cutaneous condition, is any medical condition that affects the integumentary system—the organ system that encloses the body and includes skin, nails, and related muscle and glands. The major function of t ...
is removed to be sent to a
pathologist Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used in ...
to render a microscopic
diagnosis Diagnosis is the identification of the nature and cause of a certain phenomenon. Diagnosis is used in many different disciplines, with variations in the use of logic, analytics, and experience, to determine "cause and effect". In systems enginee ...
. It is usually done under local anesthetic in a physician's office, and results are often available in 4 to 10 days. It is commonly performed by dermatologists. Skin biopsies are also done by family physicians, internists, surgeons, and other specialties. However, performed incorrectly, and without appropriate clinical information, a pathologist's interpretation of a skin biopsy can be severely limited, and therefore doctors and patients may forgo traditional biopsy techniques and instead choose
Mohs surgery Mohs surgery, developed in 1938 by a general surgeon, Frederic E. Mohs, is microscopically controlled surgery used to treat both common and rare types of skin cancer. During the surgery, after each removal of tissue and while the patient waits, ...
. There are four main types of skin biopsies: shave biopsy, punch biopsy, excisional biopsy, and incisional biopsy. The choice of the different skin biopsies is dependent on the suspected diagnosis of the skin lesion. Like most biopsies, patient consent and
anesthesia Anesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical or veterinary purposes. It may include some or all of analgesia (relief from or prevention of pain), paralysis (muscle relaxation), ...
(usually lidocaine injected into the skin) are prerequisites.


Types


Shave biopsy

A shave biopsy is done with either a small
scalpel A scalpel, lancet, or bistoury is a small and extremely sharp bladed instrument used for surgery, anatomical dissection, podiatry and various arts and crafts (either called a hobby knife or an X-acto knife.). Scalpels may be single-use disposa ...
blade or a curved razor blade. The technique is very much user skill dependent, as some surgeons can remove a small fragment of skin with minimal blemish using any one of the above tools, while others have great difficulty securing the devices. Ideally, the razor will shave only a small fragment of protruding tumor and leave the skin relatively flat after the procedure.
Hemostasis In biology, hemostasis or haemostasis is a process to prevent and stop bleeding, meaning to keep blood within a damaged blood vessel (the opposite of hemostasis is hemorrhage). It is the first stage of wound healing. This involves coagulation, ...
is obtained using light
electrocautery Cauterization (or cauterisation, or cautery) is a medical practice or technique of burning a part of a body to remove or close off a part of it. It destroys some tissue in an attempt to mitigate bleeding and damage, remove an undesired growth, or ...
, Monsel's solution, or aluminum chloride. This is the ideal method of diagnosis for basal cell cancer. It can be used to diagnose
squamous cell carcinoma Squamous-cell carcinomas (SCCs), also known as epidermoid carcinomas, comprise a number of different types of cancer that begin in squamous cells. These cells form on the surface of the skin, on the lining of hollow organs in the body, and on the ...
and melanoma-in-situ, however, the doctor's understanding of the growth of these last two cancers should be considered before one uses the shave method. The punch or incisional method is better for the latter two cancers as a false negative is less likely to occur (i.e. calling a squamous cell cancer an
actinic keratosis Actinic keratosis (AK), sometimes called solar keratosis or senile keratosis, is a pre-cancerous area of thick, scaly, or crusty skin.Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). McGraw-Hill. . Actinic k ...
or keratinous debris). Hemostasis for the shave technique can be difficult if one relies on electrocautery alone. A small "shave" biopsy often ends up being a large burn defect when the surgeon tries to control the bleeding with electrocautery alone. Pressure dressing or chemical
astringent An astringent (sometimes called adstringent) is a chemical that shrinks or constricts body tissues. The word derives from the Latin ''adstringere'', which means "to bind fast". Calamine lotion, witch hazel, and yerba mansa, a Californian pla ...
can help in hemostasis in patients taking
anticoagulant Anticoagulants, commonly known as blood thinners, are chemical substances that prevent or reduce coagulation of blood, prolonging the clotting time. Some of them occur naturally in blood-eating animals such as leeches and mosquitoes, where they ...
s.


Punch biopsy

A punch biopsy is done with a circular blade ranging in size from 1 mm to 8 mm. The blade, which is attached to a pencil-like handle, is rotated down through the epidermis and dermis, and into the
subcutaneous fat The subcutaneous tissue (), also called the hypodermis, hypoderm (), subcutis, superficial fascia, is the lowermost layer of the integumentary system in vertebrates. The types of cells found in the layer are fibroblasts, adipose cells, and macr ...
, producing a cylindrical core of tissue. An incision made with a punch biopsy is easily closed with one or two sutures. Some punch biopsies are shaped like an ellipse, although one can accomplish the same desired shape with a standard scalpel. The 1 mm and 1.5 mm punch are ideal for locations where cosmetic appearance is difficult to accomplish with the shave method. Minimal bleeding is noted with the 1 mm punch, and often the wound is left to heal without stitching for the smaller punch biopsies. The disadvantage of the 1 mm punch is that the tissue obtained is almost impossible to see at times due to small size, and the 1.5 mm biopsy is preferred in most cases. The common punch size used to diagnose most inflammatory skin conditions is the 3.5 or 4 mm punch.


Incisional biopsy

In an incisional biopsy a cut is made through the entire
dermis The dermis or corium is a layer of skin between the epidermis (with which it makes up the cutis) and subcutaneous tissues, that primarily consists of dense irregular connective tissue and cushions the body from stress and strain. It is divided ...
down to the subcutaneous fat. A punch biopsy is essentially an incisional biopsy, except it is round rather than elliptical as in most incisional biopsies done with a scalpel. Incisional biopsies can include the whole lesion (excisional), part of a lesion, or part of the affected skin plus part of the normal skin (to show the interface between normal and abnormal skin). Incisional biopsy often yield better diagnosis for deep pannicular skin diseases and more subcutaneous tissue can be obtained than a punch biopsy. Long and thin deep incisional biopsy are excellent on the lower extremities as they allow a large amount of tissue to be harvested with minimal tension on the surgical wound. Advantage of the incisional biopsy over the punch method is that hemostasis can be done more easily due to better visualization. Dog ear defects are rarely seen in incisional biopsies with length at least twice as long as the width.


Excisional biopsy

An excisional biopsy is essentially the same as incisional biopsy, except the entire lesion or tumor is included. This is the ideal method of diagnosis of small melanomas (when performed as an excision). Ideally, an entire melanoma should be submitted for diagnosis if it can be done safely and cosmetically. This excisional biopsy is often done with a narrow surgical margin to make sure the deepest thickness of the melanoma is given before prognosis is decided. However, as many
melanoma Melanoma, also redundantly known as malignant melanoma, is a type of skin cancer that develops from the pigment-producing cells known as melanocytes. Melanomas typically occur in the skin, but may rarely occur in the mouth, intestines, or eye ( ...
-in-situs are large and on the face, a physician will often chose to do multiple small punch biopsies before committing to a large excision for diagnostic purpose alone. Many prefer the small punch method for initial diagnostic value before resorting to the excisional biopsy. An initial small punch biopsy of a melanoma might say "severe cellular atypia, recommend wider excision". At this point, the clinician can be confident that an excisional biopsy can be performed without risking committing a "
false positive A false positive is an error in binary classification in which a test result incorrectly indicates the presence of a condition (such as a disease when the disease is not present), while a false negative is the opposite error, where the test result ...
" clinical diagnosis. In table above, each top image shows recommended lines for cutting out slices to be submitted for further processing. Bottom image shows which side of the slice that should be put to microtomy. Dashed lines here mean that either side could be used. The entire specimen may be sliced and submitted if the risk of malignancy is high. Otherwise the rest may be saved in fixation in case microscopy indicates further sampling.


Curettage biopsy

A curettage biopsy can be done on the surface of tumors or on small epidermal lesions with minimal to no
topical anesthetic A topical anesthetic is a local anesthetic that is used to numb the surface of a body part. They can be used to numb any area of the skin as well as the front of the eyeball, the inside of the nose, ear or throat, the anus and the genital area. Top ...
using a round
curette A curette is a surgical instrument designed for scraping or debriding biological tissue or debris in a biopsy, excision, or cleaning procedure. In form, the curette is a small hand tool, often similar in shape to a stylus; at the tip of the c ...
blade. Diagnosis of basal cell cancer can be made with some limitation, as morphology of the tumor is often disrupted. The pathologist must be informed about the type of anesthetic used, as topical anesthetic can cause artifact in the epidermal cells.
Liquid nitrogen Liquid nitrogen—LN2—is nitrogen in a liquid state at low temperature. Liquid nitrogen has a boiling point of about . It is produced industrially by fractional distillation of liquid air. It is a colorless, low viscosity liquid that is wid ...
or
cryotherapy Cryotherapy, sometimes known as cold therapy, is the local or general use of low temperatures in medical therapy. Cryotherapy may be used to treat a variety of tissue lesions. The most prominent use of the term refers to the surgical treatment, ...
can be used as a topical anesthetic, however, freezing artifacts can severely hamper the diagnosis of malignant skin cancers.


Fine needle aspirate

Needle aspiration biopsy Fine-needle aspiration (FNA) is a diagnostic procedure used to investigate lumps or masses. In this technique, a thin (23–25 gauge (0.52 to 0.64 mm outer diameter)), hollow needle is inserted into the mass for sampling of cells that, aft ...
is done with the rapid stabbing motion of the hand guiding a needle tipped syringe and the rapid sucking motion applied to the syringe. It is a method used to diagnose tumor deep in the skin or
lymph node A lymph node, or lymph gland, is a kidney-shaped organ of the lymphatic system and the adaptive immune system. A large number of lymph nodes are linked throughout the body by the lymphatic vessels. They are major sites of lymphocytes that inclu ...
s under the skin. The cellular aspirate is mounted on a glass slide and immediate diagnosis can be made with proper staining or submitted to a laboratory for final diagnosis. A fine needle aspirate can be done with simply a small bore needle and a small syringe (1 cc) that can generate rapid changes in suction pressure. Fine needle aspirate can be used to distinguish a cystic lesion from a
lipoma A lipoma is a benign tumor made of fat tissue. They are generally soft to the touch, movable, and painless. They usually occur just under the skin, but occasionally may be deeper. Most are less than in size. Common locations include upper back, ...
. Both the surgeon and the pathologist must be familiar with the method of procuring, fixing, and reading of the slide. Many centers have dedicated teams used in the harvest of fine needle aspirate.


Saucerization biopsy

A saucerization biopsy is also known as "scoop", "scallop", or "shave" excisional biopsy, or "shave" excision. A trend has occurred in dermatology over the last 10 years with the advocacy of a deep shave excision of a pigmented lesion. An author published the result of this method and advocated it as better than standard excision and less time-consuming. The added economic benefit is that many surgeons bill the procedure as an excision, rather than a shave biopsy. This saves the added time for hemostasis, instruments, and suture cost. The great disadvantage, seen years later, is the numerous scallop scars, and the appearance of a lesion called a " recurrent melanocytic nevus"; many "shave" excisions do not penetrate the dermis or subcutaneous fat enough to include the entire melanocytic lesion, and residual melanocytes regrow into the scar. The combination of scarring, inflammation, blood vessels, and atypical pigmented streaks seen in these recurrent nevi may result in the dermatoscopic appearance of a melanoma. When a second physician later examines the patient, he or she has no choice but to recommend re-excision of the scar. If one does not have access to the original pathology report, it is impossible to distinguish a recurring nevus from a severely dysplastic nevus or melanoma. As the procedure is widely practiced, it is not unusual to see a patient with dozens of scallop scars, with as many as 20% of them showing residual pigmentation. The second issue with the shave excision is fat
hernia A hernia is the abnormal exit of tissue or an organ, such as the bowel, through the wall of the cavity in which it normally resides. Various types of hernias can occur, most commonly involving the abdomen, and specifically the groin. Groin her ...
tion,
iatrogenic Iatrogenesis is the causation of a disease, a harmful complication, or other ill effect by any medical activity, including diagnosis, intervention, error, or negligence. "Iatrogenic", ''Merriam-Webster.com'', Merriam-Webster, Inc., accessed 27 ...
anetoderma, and
hypertrophic Hypertrophy is the increase in the volume of an organ or tissue due to the enlargement of its component cells. It is distinguished from hyperplasia, in which the cells remain approximately the same size but increase in number.Updated by Linda J. ...
scarring. As the deep shave excision either completely removes the full thickness of the dermis or greatly diminishes the dermal thickness, subcutaneous fat can herniate outward or pucker the skin out in an unattractive way. In areas prone to friction, this can result in pain, itching, or hypertrophic scarring.


Pathology report

A
pathology Pathology is the study of the causes and effects of disease or injury. The word ''pathology'' also refers to the study of disease in general, incorporating a wide range of biology research fields and medical practices. However, when used i ...
report is highly dependent on the quality of the biopsy that is submitted. It is not unusual to miss the diagnosis of a skin tumor or a skin biopsy due to a poorly performed or inappropriately performed skin biopsy. The clinical information provided to the pathologist will also affect the final diagnosis. An example would be a rapidly growing dome shaped tumor of the sun exposed skin. Despite doing a large wedge incision, a pathologist might call the biopsy keratin debris with characteristics of actinic keratosis. But provided with an accurate clinical information, he/she might consider the diagnosis of a well differentiated
squamous cell carcinoma Squamous-cell carcinomas (SCCs), also known as epidermoid carcinomas, comprise a number of different types of cancer that begin in squamous cells. These cells form on the surface of the skin, on the lining of hollow organs in the body, and on the ...
or
keratoacanthoma Keratoacanthoma (KA) is a common low-grade (unlikely to metastasize or invade) rapidly-growing skin tumour that is believed to originate from the hair follicle (pilosebaceous unit) and can resemble squamous cell carcinoma. The defining characteris ...
. It is not infrequent for two, three or more biopsies to be performed by different doctors for the same skin condition, before the correct diagnosis is made on the final biopsy. The method, depth, and quality of clinical data will all affect the yield of a skin biopsy. For this reason, doctors specializing in skin diseases are invaluable in the diagnosis of skin cancers and difficult skin diseases. Specific stains (PAS, DIF, etc.), and certain type of sectioning (vertical and horizontal) are often requested by an astute physician to make sure that the pathologist will have all the necessary information to make a good histological diagnosis.


References


External links


dermNetNZ website




{{DEFAULTSORT:Skin Biopsy Biopsy Dermatologic surgery