Skin biopsy
Encyclopedia
Skin biopsy is a biopsy
technique in which a skin lesion is removed and sent to the pathologist to render a microscopic diagnosis
. 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. 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
(usually lidocaine injected into the skin) are prerequisites.
blade, a curved razor blade, or a broken piece of "safety" razor. 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 leaving the skin relatively flat after the procedure. Hemostasis
is obtained using light electrocautery
, 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
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
or keratinous debris). Hemostasis for the shave technique can be difficult if one relied 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
can help in hemostasis in patients taking anticoagulant
s.
down to the subcutanous 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 subcutanous 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.
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
-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" clinical diagnosis.
using a round curette
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
or cryotherapy
can be used as a topical anesthetic, however, freezing artifacts can severely hamper the dianosis of malignant skin cancers.
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
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
. 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.
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 scars showing residual pigmentation. The second issue with the shave excision is fat hernia
tion, iatrogenic anetoderma
, and hypertrophic
scarring. As the deep shave excision either completely removes the full thickness of the dermis or greatly diminishes the dermal thickness, subcutanous 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.
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
or keratoacanthoma
. 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.
Biopsy
A biopsy is a medical test involving sampling of cells or tissues for examination. It is the medical removal of tissue from a living subject to determine the presence or extent of a disease. The tissue is generally examined under a microscope by a pathologist, and can also be analyzed chemically...
technique in which a skin lesion is removed and sent to the pathologist to render a microscopic diagnosis
Diagnosis
Diagnosis is the identification of the nature and cause of anything. Diagnosis is used in many different disciplines with variations in the use of logics, analytics, and experience to determine the cause and effect relationships...
. 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. 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
Anesthesia, or anaesthesia , traditionally meant the condition of having sensation blocked or temporarily taken away...
(usually lidocaine injected into the skin) are prerequisites.
Shave biopsy
This is done with either a small scalpelScalpel
A scalpel, or lancet, is a small and extremely sharp bladed instrument used for surgery, anatomical dissection, and various arts and crafts . Scalpels may be single-use disposable or re-usable. Re-usable scalpels can have attached, resharpenable blades or, more commonly, non-attached, replaceable...
blade, a curved razor blade, or a broken piece of "safety" razor. 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 leaving the skin relatively flat after the procedure. Hemostasis
Hemostasis
Hemostasis or haemostasis is a process which causes bleeding to stop, meaning to keep blood within a damaged blood vessel . Most of the time this includes blood changing from a liquid to a solid state. Intact blood vessels are central to moderating blood's tendency to clot...
is obtained using light electrocautery
Cauterization
The medical practice or technique of cauterization is the burning of part of a body to remove or close off a part of it in a process called cautery, which destroys some tissue, in an attempt to mitigate damage, remove an undesired growth, or minimize other potential medical harmful possibilities...
, Monsel's solution
Ferric subsulfate solution
Ferric subsulfate solution is a styptic or haemostatic agent used after superficial skin biopsies. Ferric subsulfate solution is also known as Basic Ferric Sulfate Solution 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 carcinoma
Squamous cell carcinoma , occasionally rendered as "squamous-cell carcinoma", is a histologically distinct form of cancer. It arises from the uncontrolled multiplication of malignant cells deriving from epithelium, or showing particular cytological or tissue architectural characteristics of...
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
Actinic keratosis is a premalignant condition of thick, scaly, or crusty patches of skin. It is more common in fair-skinned people. It is associated with those who are frequently exposed to the sun, as it is usually accompanied by solar damage...
or keratinous debris). Hemostasis for the shave technique can be difficult if one relied 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
Astringent
An astringent substance is a chemical compound that tends to shrink or constrict body tissues, usually locally after topical medicinal application. The word "astringent" derives from Latin adstringere, meaning "to bind fast"...
can help in hemostasis in patients taking anticoagulant
Anticoagulant
An anticoagulant is a substance that prevents coagulation of blood. A group of pharmaceuticals called anticoagulants can be used in vivo as a medication for thrombotic disorders. Some anticoagulants are used in medical equipment, such as test tubes, blood transfusion bags, and renal dialysis...
s.
Punch biopsy
This is done with a round shaped knife ranging in size from 1mm to 8 mm. 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. 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. Ideally, the punch biopsy includes the full thickness skin and subcutaneous fat in the diagnosis of skin disease.Incisional biopsy
A cut is made through the entire dermisDermis
The dermis is a layer of skin between the epidermis and subcutaneous tissues, and is composed of two layers, the papillary and reticular dermis...
down to the subcutanous 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 subcutanous 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
This 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 excisionalWide local excision
A wide local excision is a surgical procedure to remove a small area of diseased or problematic tissue with a margin of normal tissue. This procedure is commonly performed on the breast and to skin lesions, but can be used on any area of the body....
biopsy is often done with a narrow surgical margin
Surgical margin
Surgical margin, also known as tumor free margin, free margin, normal skin margin, and normal tissue margin, usually refers to the visible normal tissue or skin margin that is removed with the surgical excision of a tumor, growth, or malignancy.-Definition:Surgical margin in a surgery reports...
to make sure the deepest thickness of the melanoma is given before prognosis is decided. However, as many melanoma
Melanoma
Melanoma is a malignant tumor of melanocytes. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the 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" clinical diagnosis.
Curettage biopsy
This can be done on the surface of tumors or on small epidermal lesions with minimal to no topical anestheticTopical 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. Topical anesthetics are available in creams,...
using a round curette
Curette
A curette is a surgical instrument designed for scraping 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 curette is a small scoop, hook, or gouge...
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
Liquid nitrogen is nitrogen in a liquid state at a very low temperature. It is produced industrially by fractional distillation of liquid air. Liquid nitrogen is a colourless clear liquid with density of 0.807 g/mL at its boiling point and a dielectric constant of 1.4...
or cryotherapy
Cryotherapy
Cryotherapy is the local or general use of low temperatures in medical therapy or the removal of heat from a body part. The term "cryotherapy" comes from the Greek cryo meaning cold and the word therapy meaning cure...
can be used as a topical anesthetic, however, freezing artifacts can severely hamper the dianosis of malignant skin cancers.
Fine needle aspirate
Needle aspiration biopsyNeedle aspiration biopsy
Needle aspiration biopsy , may refer to fine needle aspiration cytology , fine needle aspiration biopsy and fine needle aspiration , is a diagnostic procedure sometimes used to investigate superficial lumps or masses...
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
Lymph node
A lymph node is a small ball or an oval-shaped organ of the immune system, distributed widely throughout the body including the armpit and stomach/gut and linked by lymphatic vessels. Lymph nodes are garrisons of B, T, and other immune cells. Lymph nodes are found all through the body, and act as...
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
Lipoma
A lipoma is a benign tumor composed of adipose tissue. It is the most common form of soft tissue tumor. Lipomas are soft to the touch, usually movable, and are generally painless. Many lipomas are small but can enlarge to sizes greater than six centimeters. Lipomas are commonly found in adults...
. 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
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 a very difficult to deal with lesions called a "recurrent melanocytic nevus", see recurrent nevus. What has happened is that many "shave" excisions do not adequately penetrate the dermis or subcutanous fat enough to include the entire melanocytic lesion. 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 then re-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 dysplasticDysplasia
Dysplasia , is a term used in pathology to refer to an abnormality of development. This generally consists of an expansion of immature cells, with a corresponding decrease in the number and location of mature cells. Dysplasia is often indicative of an early neoplastic process...
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 scars showing residual pigmentation. The second issue with the shave excision is fat hernia
Hernia
A hernia is the protrusion of an organ or the fascia of an organ through the wall of the cavity that normally contains it. A hiatal hernia occurs when the stomach protrudes into the mediastinum through the esophageal opening in the diaphragm....
tion, iatrogenic anetoderma
Anetoderma
Anetoderma is a localized laxity of the skin with herniation or outpouching resulting from abnormal dermal elastic tissue.- See also :...
, and hypertrophic
Hypertrophy
Hypertrophy is the increase in the volume of an organ or tissue due to the enlargement of its component cells. It should be distinguished from hyperplasia, in which the cells remain approximately the same size but increase in number...
scarring. As the deep shave excision either completely removes the full thickness of the dermis or greatly diminishes the dermal thickness, subcutanous 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 pathologyPathology
Pathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....
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 carcinoma
Squamous cell carcinoma , occasionally rendered as "squamous-cell carcinoma", is a histologically distinct form of cancer. It arises from the uncontrolled multiplication of malignant cells deriving from epithelium, or showing particular cytological or tissue architectural characteristics of...
or keratoacanthoma
Keratoacanthoma
Keratoacanthoma is a common low-grade skin tumour that is believed to originate from the neck of the hair follicle. Many pathologists consider it to be a form of squamous cell carcinoma...
. 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.