A dermoid cyst is a

teratoma A teratoma is a neoplasia, tumor made up of several types of biological tissue, tissue, such as hair, muscle, Human tooth, teeth, or bone. Teratomata typically form in the tailbone (where it is known as a sacrococcygeal teratoma), ovary, or test ...

of a

cyst A cyst is a closed sac, having a distinct envelope and division compared with the nearby tissue. Hence, it is a cluster of cells that have grouped together to form a sac (like the manner in which water molecules group together to form a bubb ...

ic nature that contains an array of developmentally mature, solid tissues. It frequently consists of

skin Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation. Other animal coverings, such as the arthropod exoskeleton, have different ...

hair follicles The hair follicle is an organ found in mammalian skin. It resides in the dermal layer of the skin and is made up of 20 different cell types, each with distinct functions. The hair follicle regulates hair growth via a complex interaction between ho ...

, and

sweat glands Sweat glands, also known as sudoriferous or sudoriparous glands, , are small tubular structures of the skin that produce sweat. Sweat glands are a type of exocrine gland, which are glands that produce and secrete substances onto an epithelial sur ...

, while other commonly found components include clumps of long

hair Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and ...

, pockets of

sebum A sebaceous gland or oil gland is a microscopic exocrine gland in the skin that opens into a hair follicle to secrete an oily or waxy matter, called sebum, which lubricates the hair and skin of mammals. In humans, sebaceous glands occur ...

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is com ...

fat In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers specif ...

bone A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, ...

, nail,

teeth A tooth (: teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...

eyes An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

cartilage Cartilage is a resilient and smooth type of connective tissue. Semi-transparent and non-porous, it is usually covered by a tough and fibrous membrane called perichondrium. In tetrapods, it covers and protects the ends of long bones at the joints ...

, and

thyroid The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans, it is a butterfly-shaped gland located in the neck below the Adam's apple. It consists of two connected lobes. The lower two thirds of the lobes are connected by ...

tissue. As dermoid cysts grow slowly and contain mature tissue, this type of cystic teratoma is nearly always

benign Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...

. In those rare cases wherein the dermoid cyst is

malignant Malignancy () is the tendency of a medical condition to become progressively worse; the term is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malig ...

, a

squamous cell carcinoma Squamous-cell carcinoma (SCC), also known as epidermoid carcinoma, comprises 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 ...

usually develops in adults, while infants and children usually present with an endodermal sinus tumor.Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). McGraw-Hill. .

Location

Due to its classification, a dermoid cyst can occur wherever a teratoma can occur.

Vaginal and ovarian dermoid cysts

Ovaries normally grow cyst-like structures called follicles each month. Once an egg is released from its follicle during

ovulation Ovulation is an important part of the menstrual cycle in female vertebrates where the egg cells are released from the ovaries as part of the ovarian cycle. In female humans ovulation typically occurs near the midpoint in the menstrual cycle and ...

, follicles typically deflate. Sometimes fluid accumulates inside the follicle, forming a simple (containing only fluid) cyst. The majority of these functional cysts resolve spontaneously. While all

ovarian cyst An ovarian cyst is a fluid-filled sac within the ovary. They usually cause no symptoms, but occasionally they may produce bloating, lower abdominal pain, or lower back pain. The majority of cysts are harmless. If the cyst either #Cyst rupture, br ...

s can range in size from very small to quite large, dermoid cysts are not classified as functional cysts. Dermoid cysts originate from pluripotent

germ cells A germ cell is any cell that gives rise to the gametes of an organism that reproduces sexually. In many animals, the germ cells originate in the primitive streak and migrate via the gut of an embryo to the developing gonads. There, they undergo ...

(which are present at birth) that differentiate abnormally, developing characteristics of mature dermal cells. Complications exist, such as torsion (twisting), rupture, and infection, although their incidence is rare. Dermoid ovarian cysts which are larger present complications which might require removal by either

laparoscopy Laparoscopy () is an operation performed in the abdomen or pelvis using small incisions (usually 0.5–1.5 cm) with the aid of a camera. The laparoscope aids diagnosis or therapeutic interventions with a few small cuts in the abdomen.Medli ...

or laparotomy (traditional surgery). Rarely, a dermoid cyst can develop in the vagina. File:Large ovarian cyst.JPG, Large ovarian cyst File:Dermoid cyst.jpg, Dermoid cyst in vaginal ultrasonography File:ComplexCystofaDermoid.png, A complex cyst due to a dermoid as seen on ultrasound File:DermoidCyst(CT)Mark.png, A complex cyst due to a dermoid as seen on CT. Arrow points to bone or teeth.

Periorbital dermoid cysts

Dermoid cysts can appear in young children, often near the lateral aspect of the eyebrow (right part of the right eyebrow or left part of the left eyebrow). Depending on the perceived amount of risk, these are sometimes excised or simply kept under observation. An inflammatory reaction can occur if a dermoid cyst is disrupted, and the cyst can recur if it is not completely excised. Sometimes complete excision is not practical if the cyst is in a dumbbell configuration, whereby it extends through a suture line in the skull. If dermoid cysts appear on the medial aspect, the possibility of an

encephalocele Encephalocele is a neural tube defect characterized by sac-like protrusions of the brain and the Biological membrane, membranes that cover it through openings in the human skull, skull. These defects are caused by failure of the neural tube to cl ...

becomes greater and should be considered among the differential diagnoses. Other areas where a dermoid cyst may appear are the

brain The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...

scrotum In most terrestrial mammals, the scrotum (: scrotums or scrota; possibly from Latin ''scortum'', meaning "hide" or "skin") or scrotal sac is a part of the external male genitalia located at the base of the penis. It consists of a sac of skin ...

and the

pharynx The pharynx (: pharynges) is the part of the throat behind the human mouth, mouth and nasal cavity, and above the esophagus and trachea (the tubes going down to the stomach and the lungs respectively). It is found in vertebrates and invertebrates ...

. Dermoid cysts develop during pregnancy. They occur when skin cells and things like hair, sweat glands, oil glands or fatty tissue get trapped in the skin as a baby grows in the womb. Dermoid cysts are present at birth (congenital) and are common. It can be months or years before a dermoid cyst is noticed on a child because the cysts grow slowly. Dermoid cyst symptoms are minor and the cysts are usually painless. They are not harmful to a child's health. If they become infected, the infection must be treated and the cyst should be removed. It is easier to remove cysts and prevent scars if the cyst is removed before it gets infected.

Spinal dermoid cysts

Spinal dermoid cysts are benign ectopic growths thought to be a consequence of embryology errors during

neural tube In the developing chordate (including vertebrates), the neural tube is the embryonic precursor to the central nervous system, which is made up of the brain and spinal cord. The neural groove gradually deepens as the neural folds become elevated, ...

closure. Their reported incidence is extremely rare, accounting for less than 1% of intramedullary

spinal cord The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal c ...

tumours. It has been proposed that a possible 180 cases of spinal dermoid tumours have been identified over the past century in the literature. Dermoid cysts more often involve the lumbosacral region than the

thoracic vertebrae In vertebrates, thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. In humans, there are twelve thoracic vertebra (anatomy), vertebrae of intermediate size between the ce ...

and are extramedullary presenting in the first decade of life. Various hypotheses have been advanced to explain the pathogenesis of spinal dermoids, the origin of which may be acquired or congenital. * Acquired or iatrogenic dermoids may arise from the implantation of epidermal tissue into the subdural space i.e. spinal cutaneous inclusion, during needle puncture (e.g. lumbar puncture) or during surgical procedures on closure of a dysraphic malformation. * Congenital dermoids, however, are thought to arise from cells whose position is correct but which fail to differentiate into the correct cell-type. The long-time held belief was that the inclusion of cutaneous ectodermal cells occurred early in embryonic life, and the displaced

pluripotent Cell potency is a cell's ability to differentiate into other cell types. The more cell types a cell can differentiate into, the greater its potency. Potency is also described as the gene activation potential within a cell, which like a continuum ...

cells developed into a dermoid lesion. Spinal abnormalities, e.g. intramedullary dermoid cysts may arise more frequently in the lumbosacral region (quite often at the level of the

conus medullaris The conus medullaris (Latin for "medullary cone") or conus terminalis is the tapered, lower end of the spinal cord. It occurs near lumbar vertebral levels 1 (L1) and 2 (L2), occasionally lower. The upper end of the conus medullaris is usually no ...

) and may be seen with other congenital anomalies of the spine including posterior

spina bifida Spina bifida (SB; ; Latin for 'split spine') is a birth defect in which there is incomplete closing of the vertebral column, spine and the meninges, membranes around the spinal cord during embryonic development, early development in pregnancy. T ...

occulta as identified by the neuroradiological analysis.

Diagnosis

Differential diagnosis

A small dermoid cyst on the

coccyx The coccyx (: coccyges or coccyxes), commonly referred to as the tailbone, is the final segment of the vertebral column in all apes, and analogous structures in certain other mammals such as horse anatomy, horses. In tailless primates (e.g. hum ...

can be difficult to distinguish from a pilonidal cyst. This is partly because both can be full of hair. A pilonidal cyst is a

pilonidal sinus Pilonidal disease is a type of skin infection that typically occurs as a cyst between the cheeks of the buttocks and often at the upper end. Symptoms may include pain, swelling, and redness. There may also be drainage of fluid, but rarely a feve ...

that is obstructed. Any teratoma near the body surface may develop a sinus or a fistula, or even a cluster of these. Such is the case of Canadian Football League linebacker

Tyrone Jones Tyrone Jones (August 3, 1961 – June 10, 2008) was a gridiron football all-star and Grey Cup champion linebacker in the Canadian Football League. Born in St. Mary's, Georgia, Ty's football career began at Camden County High School, Camden Cou ...

, whose teratoma was discovered when he blew a tooth out of his nose.

Treatment

Treatment for dermoid cyst is complete surgical removal, preferably in one piece and without any spillage of cyst contents. Marsupialization, a surgical technique often used to treat pilonidal cyst, is inappropriate for dermoid cyst due to the risk of malignancy. The association of dermoid cysts with pregnancy has been increasingly reported. They usually present the dilemma of weighing the risks of surgery and anesthesia versus the risks of untreated adnexal mass. Most references state that it is more feasible to treat bilateral dermoid cysts of the ovaries discovered during pregnancy if they grow beyond 6 cm in diameter.

References

External links

{{DEFAULTSORT:Dermoid Cyst Cutaneous congenital anomalies Gynaecologic disorders Germ cell neoplasia Eye diseases