A dermoid cyst is a

teratoma A teratoma is a tumor made up of several different types of tissue, such as hair, muscle, teeth, or bone. Teratomata typically form in the ovary, testicle, or coccyx. Symptoms Symptoms may be minimal if the tumor is small. A testicular terato ...

of a

cyst A cyst is a closed sac, having a distinct envelope and cell division, division compared with the nearby Biological tissue, tissue. Hence, it is a cluster of Cell (biology), cells that have grouped together to form a sac (like the manner in which ...

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 cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...

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 h ...

, 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 f ...

, pockets of

sebum A sebaceous 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 in the greatest nu ...

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 in the c ...

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 spec ...

bone A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...

nail Nail or Nails may refer to: In biology * Nail (anatomy), toughened protective protein-keratin (known as alpha-keratin, also found in hair) at the end of an animal digit, such as fingernail * Nail (beak), a plate of hard horny tissue at the tip ...

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 Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conve ...

cartilage Cartilage is a resilient and smooth type of connective tissue. In tetrapods, it covers and protects the ends of long bones at the joints as articular cartilage, and is a structural component of many body parts including the rib cage, the neck an ...

, and

thyroid The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans it is in the neck and consists of two connected lobes. The lower two thirds of the lobes are connected by a thin band of tissue called the thyroid isthmus. The thy ...

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. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous benign tumor, ''benign'' tumor in that a malign ...

. In those rare cases wherein the dermoid cyst is

malignant Malignancy () is the tendency of a medical condition to become progressively worse. Malignancy is most familiar as a characterization of cancer. A ''malignant'' tumor contrasts with a non-cancerous ''benign'' tumor in that a malignancy is not s ...

, a

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 ...

usually develops in adults, while infants and children usually present with an

endodermal sinus tumor Endodermal sinus tumor (EST) is a member of the germ cell tumor group of cancers. It is the most common testicular tumor in children under three, and is also known as infantile embryonal carcinoma. This age group has a very good prognosis. In contr ...

.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 the release of eggs from the ovaries. In women, this event occurs when the ovarian follicles rupture and release the secondary oocyte ovarian cells. After ovulation, during the luteal phase, the egg will be available to be fertilized ...

, 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. Often they cause no symptoms. Occasionally they may produce bloating, lower abdominal pain, or lower back pain. The majority of cysts are harmless. If the cyst either breaks open or causes ...

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 Germ or germs may refer to: Science * Germ (microorganism), an informal word for a pathogen * Germ cell, cell that gives rise to the gametes of an organism that reproduces sexually * Germ layer, a primary layer of cells that forms during embr ...

(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 Vaginal ultrasonography is a medical ultrasonography that applies an ultrasound transducer (or "probe") in the vagina to visualize organs within the pelvic cavity. It is also called transvaginal ultrasonography because the ultrasound waves go ''a ...

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 membranes that cover it through openings in the skull. These defects are caused by failure of the neural tube to close completely during fetal develop ...

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

brain A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a v ...

scrotum The scrotum or scrotal sac is an anatomical male reproductive structure located at the base of the penis that consists of a suspended dual-chambered sac of skin and smooth muscle. It is present in most terrestrial male mammals. The scrotum cont ...

and the

pharynx The pharynx (plural: pharynges) is the part of the throat behind the mouth and nasal cavity, and above the oesophagus and trachea (the tubes going down to the stomach and the lungs). It is found in vertebrates and invertebrates, though its struc ...

. 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 fold become elevated, a ...

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, which extends from the medulla oblongata in the brainstem to the lumbar region of the vertebral column (backbone). The backbone encloses the central canal of the spi ...

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 The vertebral column, also known as the backbone or spine, is part of the axial skeleton. The vertebral column is the defining characteristic of a vertebrate in which the notochord (a flexible rod of uniform composition) found in all chordates ...

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 and they are intermediate in size b ...

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 Pluripotency: These are the cells that can generate into any of the three Germ layers which imply Endodermal, Mesodermal, and Ectodermal cells except tissues like the placenta. According to Latin terms, Pluripotentia means the ability for many thin ...

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 ''Conus'' is a genus of predatory sea snails, or cone snails, marine gastropod mollusks in the family Conidae.Bouchet, P.; Gofas, S. (2015). Conus Linnaeus, 1758. In: MolluscaBase (2015). Accessed through: World Register of Marine Species at ...

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

spina bifida Spina bifida (Latin for 'split spine'; SB) is a birth defect in which there is incomplete closing of the spine and the membranes around the spinal cord during early development in pregnancy. There are three main types: spina bifida occulta, me ...

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 horses. In tailless primates (e.g. humans and othe ...

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 which typically occurs as a cyst Intergluteal cleft, 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 flui ...

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 Coun ...

, 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 400px, Marsupialization Marsupialization is the surgical technique of cutting a slit into an abscess or cyst and suturing the edges of the slit to form a continuous surface from the exterior surface to the interior surface of the cyst or abscess. ...

, a surgical technique often used to treat

pilonidal cyst Pilonidal disease is a type of skin infection which typically occurs as a cyst Intergluteal cleft, 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 flui ...

, 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 In anatomy, adnexa (plural) refers to the appendage An appendage (or outgrowth) is an external body part, or natural prolongation, that protrudes from an organism's body. In arthropods, an appendage refers to any of the homologous body parts ...

. 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