Sebaceous cyst
Encyclopedia
A sebaceous cyst is a term that loosely refers to either epidermoid cyst
s (also known as epidermal cysts; L72.0
) or pilar cysts (also known as trichilemmal cysts; L72.1
). Because an epidermoid cyst originates in the epidermis and a pilar cyst
originates from hair follicles, by definition, neither type of cyst
is strictly a sebaceous cyst. The name is regarded as a misnomer as the fatty, white, semi-solid material in both of these cyst
entities is not sebum, but keratin
. Furthermore, under the microscope neither entity contains sebaceous glands. In practice, however, the terms are often used interchangeably.
"True" sebaceous cysts are relatively rare and are known as steatocystomas
or, if multiple, as steatocystoma multiplex
.
The scalp
, ear
s, back
, face
, and upper arm, are common sites for sebaceous cysts, though they may occur anywhere on the body except the palms of the hand
s and soles
of the feet. In males a common place for them to develop is the scrotum
and chest
. They are more common in hairier areas, where in cases of long duration they could result in hair loss on the skin surface immediately above the cyst. They are smooth to the touch, vary in size, and are generally round in shape.
They are generally mobile masses that can consist of:
The nature of the contents of a sebaceous cyst, and of its surrounding capsule, will be determined by whether the cyst has ever been infected.
With surgery, a cyst can usually be excised in its entirety. Poor surgical technique or previous infection leading to scarring and tethering of the cyst to the surrounding tissue may lead to rupture during excision and removal. A completely removed cyst will not recur, though if the patient has a predisposition to cyst formation, further cysts may develop in the same general area.
s, swollen hair follicle
s, and excessive testosterone
production will cause such cysts.
A case has been reported of sebaceous cyst being caused by Dermatobia hominis.
Hereditary causes of sebaceous cysts include Gardner's syndrome
and basal cell nevus syndrome.
excision of a sebaceous cyst is a simple procedure to completely remove the sac and its contents.
There are three general approaches used: traditional wide excision, minimal excision, and punch biopsy excision.
The typical outpatient surgical procedure for cyst removal is to numb the area around the cyst with a local anaesthetic, then to use a scalpel
to open the lesion with either a single cut down the center of the swelling, or an oval cut on both sides of the centerpoint. If the cyst is small, it may be lanced instead. The person performing the surgery will squeeze out the keratin
(the semi-solid material consisting principally of sebum and dead skin cells) surrounding the cyst, then use blunt-headed scissors or another instrument to hold the incision wide open while using fingers or forceps to try to remove the cyst intact. If the cyst can be removed in one piece, the "cure rate" is 100%. If, however, it is fragmented and cannot be entirely recovered, the operator may use curettage
(scraping) to remove the remaining exposed fragments, then burn them with an electro-cauterization
tool, in an effort to destroy them in place. In such cases the cyst may or may not recur. In either case, the incision is then disinfected and, if necessary, the skin is stitched back together over it. A scar
will most likely result.
In some cases where "cure rate" is not 100% the resulting hole is filled with an antiseptic ribbon after washing it with an iodine based solution. This is then covered with a field dressing. The ribbon and the dressing are to be changed once or twice daily for 7–10 days after which the incision is sewn up or allowed to close by secondary intention, i.e. by forming granulation tissue and healing "from the bottom up."
An infected cyst may require oral antibiotic
s or other treatment before and/or after excision.
An approach involving incision, rather than excision, has also been proposed.
directly on the cyst for about fifteen minutes, twice daily, for about 10 days (depending on size and location of the cyst) to promote drainage.
Epidermoid cyst
An epidermoid cyst is a benign cyst usually found on the skin. The cyst develops out of ectodermal tissue. Histologically, it is made of a thin layer of squamous epithelium.-Terminology:...
s (also known as epidermal cysts; L72.0
ICD-10 Chapter XII: Diseases of the skin and subcutaneous tissue
- Infections of the skin and subcutaneous tissue :* Staphylococcal scalded skin syndrome* Impetigo** Impetigo*** Bockhart's impetigo** Impetiginization of other dermatoses* Cutaneous abscess, furuncle and carbuncle* Cellulitis...
) or pilar cysts (also known as trichilemmal cysts; L72.1
ICD-10 Chapter XII: Diseases of the skin and subcutaneous tissue
- Infections of the skin and subcutaneous tissue :* Staphylococcal scalded skin syndrome* Impetigo** Impetigo*** Bockhart's impetigo** Impetiginization of other dermatoses* Cutaneous abscess, furuncle and carbuncle* Cellulitis...
). Because an epidermoid cyst originates in the epidermis and a pilar cyst
Trichilemmal cyst
A trichilemmal cyst, also known as a wen, pilar cyst or isthmus-catagen cyst, is a common cyst that forms from a hair follicle. They are most often found on the scalp. The cysts are smooth, mobile and filled with keratin, a protein component found in hair, nails, and skin. They may or may not be...
originates from hair follicles, by definition, neither type of cyst
Cyst
A cyst is a closed sac, having a distinct membrane and division on the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.- Locations :* Acne...
is strictly a sebaceous cyst. The name is regarded as a misnomer as the fatty, white, semi-solid material in both of these cyst
Cyst
A cyst is a closed sac, having a distinct membrane and division on the nearby tissue. It may contain air, fluids, or semi-solid material. A collection of pus is called an abscess, not a cyst. Once formed, a cyst could go away on its own or may have to be removed through surgery.- Locations :* Acne...
entities is not sebum, but keratin
Keratin
Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...
. Furthermore, under the microscope neither entity contains sebaceous glands. In practice, however, the terms are often used interchangeably.
"True" sebaceous cysts are relatively rare and are known as steatocystomas
Steatocystoma simplex
Steatocystoma simplex is a cutaneous condition characterized by a skin lesion that occurs with equal frequency in adult women and men, occurring on the face, trunk, or extremities....
or, if multiple, as steatocystoma multiplex
Steatocystoma multiplex
Steatocystoma multiplex is a benign, autosomal dominant congenital condition resulting in multiple cysts on a person's body....
.
Presentation
Scalp
The scalp is the anatomical area bordered by the face anteriorly and the neck to the sides and posteriorly.-Layers:It is usually described as having five layers, which can conveniently be remembered as a mnemonic:...
, ear
Ear
The ear is the organ that detects sound. It not only receives sound, but also aids in balance and body position. The ear is part of the auditory system....
s, back
Back
- People :* Adam Back, British cryptographer* Charles Back, South African winemaker* Chris Back , Australian politician* Ernst Emil Alexander Back , German physicist* Frédéric Back , Canadian animator...
, face
Face
The face is a central sense organ complex, for those animals that have one, normally on the ventral surface of the head, and can, depending on the definition in the human case, include the hair, forehead, eyebrow, eyelashes, eyes, nose, ears, cheeks, mouth, lips, philtrum, temple, teeth, skin, and...
, and upper arm, are common sites for sebaceous cysts, though they may occur anywhere on the body except the palms of the hand
Hand
A hand is a prehensile, multi-fingered extremity located at the end of an arm or forelimb of primates such as humans, chimpanzees, monkeys, and lemurs...
s and soles
Sole (foot)
The sole is the bottom of the foot.In humans the sole of the foot is anatomically referred to as the plantar aspect. The equivalent surface in ungulates is the hoof.- Human sole :...
of the feet. In males a common place for them to develop is the scrotum
Scrotum
In some male mammals the scrotum is a dual-chambered protuberance of skin and muscle containing the testicles and divided by a septum. It is an extension of the perineum, and is located between the penis and anus. In humans and some other mammals, the base of the scrotum becomes covered with curly...
and chest
Chest
The chest is a part of the anatomy of humans and various other animals. It is sometimes referred to as the thorax or the bosom.-Chest anatomy - Humans and other hominids:...
. They are more common in hairier areas, where in cases of long duration they could result in hair loss on the skin surface immediately above the cyst. They are smooth to the touch, vary in size, and are generally round in shape.
They are generally mobile masses that can consist of:
- Fibrous tissues and fluids
- A fatty, (keratinous), substance that resembles cottage cheeseCottage cheeseCottage cheese is a cheese curd product with a mild flavor. It is drained, but not pressed, so some whey remains and the individual curds remain loose. The curd is usually washed to remove acidity, giving sweet curd cheese. It is not aged or colored. Different styles of cottage cheese are made from...
, in which case the cyst may be called "keratin cyst" This material has a characteristic "cheesy" or "foot odor" smell. - A somewhat viscous, serosanguineous fluid (containing purulent and bloody material)
The nature of the contents of a sebaceous cyst, and of its surrounding capsule, will be determined by whether the cyst has ever been infected.
With surgery, a cyst can usually be excised in its entirety. Poor surgical technique or previous infection leading to scarring and tethering of the cyst to the surrounding tissue may lead to rupture during excision and removal. A completely removed cyst will not recur, though if the patient has a predisposition to cyst formation, further cysts may develop in the same general area.
Causes
Blocked sebaceous glandSebaceous gland
The sebaceous glands are microscopic glands in the skin that secrete an oily/waxy matter, called sebum, to lubricate and waterproof the skin and hair of mammals...
s, swollen hair follicle
Hair follicle
A hair follicle is a skin organ that produces hair. Hair production occurs in phases, including a growth phase , and cessation phase , and a rest phase . Stem cells are principally responsible for the production of hair....
s, and excessive testosterone
Testosterone
Testosterone is a steroid hormone from the androgen group and is found in mammals, reptiles, birds, and other vertebrates. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands...
production will cause such cysts.
A case has been reported of sebaceous cyst being caused by Dermatobia hominis.
Hereditary causes of sebaceous cysts include Gardner's syndrome
Gardner's syndrome
Gardner syndrome, also known as familial colorectal polyposis, is an autosomal dominant form of polyposis characterized by the presence of multiple polyps in the colon together with tumors outside the colon...
and basal cell nevus syndrome.
Treatment
Sebaceous cysts generally do not require medical treatment. However, if they continue to grow, they may become unsightly, painful, infected, or all of the above.Surgical
SurgicalSurgery
Surgery is an ancient medical specialty that uses operative manual and instrumental techniques on a patient to investigate and/or treat a pathological condition such as disease or injury, or to help improve bodily function or appearance.An act of performing surgery may be called a surgical...
excision of a sebaceous cyst is a simple procedure to completely remove the sac and its contents.
There are three general approaches used: traditional wide excision, minimal excision, and punch biopsy excision.
The typical outpatient surgical procedure for cyst removal is to numb the area around the cyst with a local anaesthetic, then to use a scalpel
Scalpel
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...
to open the lesion with either a single cut down the center of the swelling, or an oval cut on both sides of the centerpoint. If the cyst is small, it may be lanced instead. The person performing the surgery will squeeze out the keratin
Keratin
Keratin refers to a family of fibrous structural proteins. Keratin is the key of structural material making up the outer layer of human skin. It is also the key structural component of hair and nails...
(the semi-solid material consisting principally of sebum and dead skin cells) surrounding the cyst, then use blunt-headed scissors or another instrument to hold the incision wide open while using fingers or forceps to try to remove the cyst intact. If the cyst can be removed in one piece, the "cure rate" is 100%. If, however, it is fragmented and cannot be entirely recovered, the operator may use curettage
Curettage
Curettage, in medical procedures, is the use of a curette to remove tissue by scraping or scooping.Curettages are also a declining method of abortion. It has been replaced by vacuum aspiration over the last decade....
(scraping) to remove the remaining exposed fragments, then burn them with an electro-cauterization
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...
tool, in an effort to destroy them in place. In such cases the cyst may or may not recur. In either case, the incision is then disinfected and, if necessary, the skin is stitched back together over it. A scar
Scar
Scars are areas of fibrous tissue that replace normal skin after injury. A scar results from the biological process of wound repair in the skin and other tissues of the body. Thus, scarring is a natural part of the healing process. With the exception of very minor lesions, every wound results in...
will most likely result.
In some cases where "cure rate" is not 100% the resulting hole is filled with an antiseptic ribbon after washing it with an iodine based solution. This is then covered with a field dressing. The ribbon and the dressing are to be changed once or twice daily for 7–10 days after which the incision is sewn up or allowed to close by secondary intention, i.e. by forming granulation tissue and healing "from the bottom up."
An infected cyst may require oral antibiotic
Antibiotic
An antibacterial is a compound or substance that kills or slows down the growth of bacteria.The term is often used synonymously with the term antibiotic; today, however, with increased knowledge of the causative agents of various infectious diseases, antibiotic has come to denote a broader range of...
s or other treatment before and/or after excision.
An approach involving incision, rather than excision, has also been proposed.
Non-surgical
Another method of treatment involves placement of a heating padHeating pad
A heating pad is a pad used for warming of parts of the body in order to manage pain. Localized application of heat causes the blood vessels in that area to dilate, enhancing perfusion to the targeted tissue...
directly on the cyst for about fifteen minutes, twice daily, for about 10 days (depending on size and location of the cyst) to promote drainage.
External links
- Overview at University of Maryland Medical Center
- Sebaceous Cyst (Epidermal Cyst) - Pictures, Causes, Treatment and Removal - PrimeHealthChannel.com