Dermoid cyst
Encyclopedia
A dermoid cyst is a cyst
ic teratoma
that contains developmentally mature skin
complete with hair follicles and sweat glands, sometimes clumps of long hair
, and often pockets of sebum, blood
, fat
, bone
, nails
, teeth, eyes, cartilage
, and thyroid
tissue. Because it contains mature tissue, a dermoid cyst is almost always benign. The rare malignant
dermoid cyst usually develops squamous cell carcinoma
in adults; in babies and children it usually develops endodermal sinus tumor
.
Some authors use the term dermoid cyst as a frank synonym for teratoma, meaning any teratoma, regardless of its histology or location. Others use it to mean any mature, cystic teratoma. These uses appear to be most common in gynecology and dermatology.
Dermoid cysts can recur if not completely excised. Sometimes, complete excision is not practical if in a dumbbell configuration where the cyst extends through a suture line in the skull.
If the dermoid cysts appear on the medial aspect, the possibility of an encephalocele
becomes greater and should be considered among the differential diagnosis.
closure. Their reported incidence is extremely rare, accounting for less than 1% of intramedullary spinal cord
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
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.
Spinal abnormalities, e.g. intramedullary dermoid cysts may arise more frequently in the lumbosacral region (quite often at the level of the conus medullaris) and may be seen with other congenital anomalies of the spine including posterior spina bifida
occulta as identified by the neuroradiological analysis .
, 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. This is usually performed through laparotomy or very carefully through laparoscopy and should preferably be done in the second trimester.
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 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, whose teratoma was discovered when he blew a tooth out of his nose.
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...
ic teratoma
Teratoma
A teratoma is an encapsulated tumor with tissue or organ components resembling normal derivatives of all three germ layers. There are rare occasions when not all three germ layers are identifiable...
that contains developmentally mature skin
Human skin
The human skin is the outer covering of the body. In humans, it is the largest organ of the integumentary system. The skin has multiple layers of ectodermal tissue and guards the underlying muscles, bones, ligaments and internal organs. Human skin is similar to that of most other mammals,...
complete with hair follicles and sweat glands, sometimes clumps of long hair
Hair
Hair is a filamentous biomaterial, that grows from follicles found in the dermis. Found exclusively in mammals, hair is one of the defining characteristics of the mammalian class....
, and often pockets of sebum, blood
Blood
Blood is a specialized bodily fluid in animals that delivers necessary substances such as nutrients and oxygen to the cells and transports metabolic waste products away from those same cells....
, fat
Fat
Fats consist of a wide group of compounds that are generally soluble in organic solvents and generally insoluble in water. Chemically, fats are triglycerides, triesters of glycerol and any of several fatty acids. Fats may be either solid or liquid at room temperature, depending on their structure...
, bone
Bone
Bones are rigid organs that constitute part of the endoskeleton of vertebrates. They support, and protect the various organs of the body, produce red and white blood cells and store minerals. Bone tissue is a type of dense connective tissue...
, nails
Nail (anatomy)
A nail is a horn-like envelope covering the dorsal aspect of the terminal phalanges of fingers and toes in humans, most non-human primates, and a few other mammals. Nails are similar to claws, which are found on numerous other animals....
, teeth, eyes, cartilage
Cartilage
Cartilage is a flexible connective tissue found in many areas in the bodies of humans and other animals, including the joints between bones, the rib cage, the ear, the nose, the elbow, the knee, the ankle, the bronchial tubes and the intervertebral discs...
, and thyroid
Thyroid
The thyroid gland or simply, the thyroid , in vertebrate anatomy, is one of the largest endocrine glands. The thyroid gland is found in the neck, below the thyroid cartilage...
tissue. Because it contains mature tissue, a dermoid cyst is almost always benign. The rare malignant
Cancer
Cancer , known medically as a malignant neoplasm, is a large group of different diseases, all involving unregulated cell growth. In cancer, cells divide and grow uncontrollably, forming malignant tumors, and invade nearby parts of the body. The cancer may also spread to more distant parts of the...
dermoid cyst usually develops 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...
in adults; in babies and children it usually develops endodermal sinus tumor
Endodermal sinus tumor
Endodermal sinus tumor , also known as yolk sac tumor , is a member of the germ cell tumor group of cancers. It is the most common testicular tumor in children under 3, and is also known as infantile embryonal carcinoma. This age group has a very good prognosis...
.
Some authors use the term dermoid cyst as a frank synonym for teratoma, meaning any teratoma, regardless of its histology or location. Others use it to mean any mature, cystic teratoma. These uses appear to be most common in gynecology and dermatology.
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). They often have a rubbery feel. These are sometimes watched and sometimes excised. An inflammatory reaction can occur if the dermoid cyst is disrupted.Dermoid cysts can recur if not completely excised. Sometimes, complete excision is not practical if in a dumbbell configuration where the cyst extends through a suture line in the skull.
If the dermoid cysts appear on the medial aspect, the possibility of an encephalocele
Encephalocele
Encephalocele, sometimes known by the Latin name cranium bifidum, 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...
becomes greater and should be considered among the differential diagnosis.
Spinal Dermoid Cysts
Spinal dermoid cysts are benign ectopic growths thought to be a consequence of embryology errors during neural tubeNeural tube
In the developing vertebrate, the neural tube is the embryo's precursor to the central nervous system, which comprises the brain and spinal cord...
closure. Their reported incidence is extremely rare, accounting for less than 1% of intramedullary spinal cord
Spinal cord
The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...
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
Thoracic vertebrae
In human anatomy, twelve thoracic vertebrae compose the middle segment of the vertebral column, between the cervical vertebrae and the lumbar vertebrae. They are intermediate in size between those of the cervical and lumbar regions; they increase in size as one proceeds down the spine, the upper...
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 fail to differentiateCellular differentiationIn developmental biology, cellular differentiation is the process by which a less specialized cell becomes a more specialized cell type. Differentiation occurs numerous times during the development of a multicellular organism as the organism changes from a simple zygote to a complex system of...
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 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) and may be seen with other congenital anomalies of the spine including posterior spina bifida
Spina bifida
Spina bifida is a developmental congenital disorder caused by the incomplete closing of the embryonic neural tube. Some vertebrae overlying the spinal cord are not fully formed and remain unfused and open. If the opening is large enough, this allows a portion of the spinal cord to protrude through...
occulta as identified by the neuroradiological analysis .
Treatment
Treatment for dermoid cyst is complete surgical removal, preferably in one piece and without any spillage of cyst contents. MarsupializationMarsupialization
Marsupialization is the surgical technique of cutting a slit into a cyst and suturing the edges of the slit to form a continuous surface from the exterior to the interior of the cyst. Sutured in this fashion, the cyst remains open and can drain freely...
, 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
Adnexal mass
An adnexal mass is a lump in tissue of the adnexa of uterus, usually in the ovary or fallopian tube. Adnexal masses can be benign or cancerous.-Causes:...
. 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. This is usually performed through laparotomy or very carefully through laparoscopy and should preferably be done in the second trimester.
Differential diagnosis
A small dermoid cyst on the coccyxCoccyx
The coccyx , commonly referred to as the tailbone, is the final segment of the vertebral column. Comprising three to five separate or fused vertebrae below the sacrum, it is attached to the sacrum by a fibrocartilaginous joint, the sacrococcygeal symphysis, which permits limited movement between...
can be difficult to distinguish from a pilonidal cyst
Pilonidal cyst
A pilonidal cyst, also referred to as a pilonidal abscess, pilonidal sinus or sacrococcygeal fistula, is a cyst or abscess near or on the natal cleft of the buttocks that often contains hair and skin debris.-Etymology:...
. This is partly because both can be full of hair. A pilonidal cyst is a pilonidal sinus 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, whose teratoma was discovered when he blew a tooth out of his nose.
See also
- Ovarian cystOvarian cystAn ovarian cyst is any collection of fluid, surrounded by a very thin wall, within an ovary. Any ovarian follicle that is larger than about two centimeters is termed an ovarian cyst. An ovarian cyst can be as small as a pea, or larger than an orange....
- CystCystA 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...
- Dermoid sinusDermoid sinusDermoid sinus is a genetic, autosomal skin condition in dogs. It is also known as pilonidal sinus because it resembles pilonidal sinus in humans. However, unlike pilonidal sinus in humans, dermoid sinus in dogs is a neural tube defect. Dermoid sinus is sometimes also confused with dermoid cyst...
, more commonly known as a pilonidal cystPilonidal cystA pilonidal cyst, also referred to as a pilonidal abscess, pilonidal sinus or sacrococcygeal fistula, is a cyst or abscess near or on the natal cleft of the buttocks that often contains hair and skin debris.-Etymology:... - Proliferating trichilemmal cystProliferating trichilemmal cystProliferating trichilemmal cysts are a cutaneous condition characterized by proliferations of squamous cells forming scroll-like structures....
- List of cutaneous conditions