periapical cyst

cyst

[sist] 1. bladder.2. an abnormal closed epithelium-lined sac in the body that contains a liquid or semisolid substance. Most are harmless, but they should be removed when possible because they occasionally may change into malignant growths, become infected, or obstruct a gland. There are four main types of cysts: retention cysts, exudation cysts, embryonic cysts, and parasitic cysts.3. a stage in the life cycle of certain parasites, during which they are enveloped in a protective wall.adventitious cyst pseudocyst (def. 1).alveolar c's dilatations of pulmonary alveoli, which may fuse by breakdown of their septa to form large air cysts (pneumatoceles).arachnoid cyst a fluid-filled cyst between the layers of the leptomeninges, lined with arachnoid membrane, usually in the sylvian fissure.Baker cyst a swelling on the back of the knee, due to escape of synovial fluid that has become enclosed in a sac of membrane.Bartholin cyst a mucus-filled cyst of a Bartholin gland, usually developing as a consequence of an obstruction of the duct by trauma, infection, epithelial hyperplasia, or congenital atresia or narrowing.Blessig c's cystic spaces formed at the periphery of the retina.blue dome cyst 1. a benign retention cyst of the breast that shows a pale blue color. See also cystic disease of breast.2. a cyst due to endometriosis, found in healed wounds such as those of an episiotomy or an incision for a cesarean section; it is usually found in the vaginal fornix or on the cervix.Boyer cyst an enlargement of the subhyoid bursa.branchial cyst (branchiogenic cyst) (branchiogenous cyst) see branchial cyst.bronchogenic cyst a congenital cyst, usually in the mediastinum or lung, arising from anomalous budding during formation of the tracheobronchial tree, lined with bronchial epithelium that may contain secretory elements.chocolate cyst one filled with hemosiderin, causing a dark color, following local hemorrhage, such as may occur in the ovary in ovarian endometriosis.choledochal cyst a congenital cystic dilatation of the common bile duct, which may cause pain in the right upper quadrant, jaundice, fever, or vomiting, or be asymptomatic.daughter cyst a small parasitic cyst developed from the walls of a larger cyst.dentigerous cyst an cyst" >odontogenic cyst surrounding the crown of a tooth, originating after the crown is completely formed.dermoid cyst see dermoid cyst.duplication cyst a congenital cystic malformation of the alimentary tract, consisting of a duplication of the segment to which it is adjacent, occurring anywhere from the mouth to the anus but most frequently affecting the ileum and esophagus.echinococcus cyst hydatid cyst.embryonic cyst one developing from bits of embryonic tissue that have been overgrown by other tissues, or from developing organs that normally disappear before birth. An example is a branchial cyst.enteric cyst (enterogenous cyst) a cyst of the intestine arising or developing from some fold or pouch along the intestinal tract. Called also enterocyst and enterocystoma.epidermal cyst (epidermoid cyst) an intradermal or subcutaneous cyst containing keratinizing squamous epithelium; it arises from occluded hair follicles. Called also wen.epidermal inclusion cyst a type of cyst" >epidermal cyst occurring on the head, neck, or trunk, formed by keratinizing squamous epithelium with a granular layer.epithelial cyst 1. any cyst lined by keratinizing stratified squamous epithelium, found most often in the skin.2. epidermal cyst.exudation cyst a cyst formed by the slow seepage of an exudate into a closed cavity.false cyst pseudocyst (def. 1).follicular cyst one due to occlusion of the duct of a follicle or small gland, especially one formed by enlargement of a graafian follicle as a result of accumulated transudate.hydatid cyst the larval stage of the tapeworms Echinococcus granulosis and E. multilocularis; each one contains daughter cysts that have many scoleces (mouths). See also hydatid disease. Called also echinococcus cyst and hydatid.inclusion cyst one formed by the inclusion of a small portion of epithelium or mesothelium within connective tissue along a line of fusion of embryonic processes; several types are found in the oral and nasal regions.keratinizing cyst one arising in the pilosebaceous apparatus, lined by stratified squamous epithelium and containing largely macerated keratin and often sufficient sebum to render the contents greasy or rancid.meibomian cyst chalazion.mucus retention cyst a mucus-containing cyst" >retention cyst caused by blockage of a salivary gland duct.multilocular cyst 1. a cyst containing several loculi or spaces.2. a cyst" >hydatid cyst with many small irregular cavities that may contain scoleces but generally little fluid.3. a thick-walled cyst in the kidney, found in clusters and usually unilaterally. In children it contains blastema and may develop into a Wilms tumor.myxoid cyst a nodular lesion usually overlying a distal interphalangeal finger joint in the dorsolateral or dorsomesial position, consisting of focal mucinous degeneration of the collagen of the dermis; not a true cyst, lacking an epithelial wall, it does not communicate with the underlying synovial space.Naboth's c's (nabothian c's) cysts that occur when mucus-producing glands in the columnar epithelium of the uterine cervix become covered over by squamous epithelium resulting from metaplasia; they are usually found in the transformation zone of the cervix. Called also Naboth's or nabothian follicles.nasoalveolar cyst (nasolabial cyst) a fissural cyst arising outside the bones at the junction of the globular portion of the medial nasal process, lateral nasal process, and maxillary process.odontogenic cyst one derived from epithelium, usually containing fluid or semisolid material, which develops during various stages of odontogenesis; nearly always enclosed within bone.parasitic cyst one forming around larval parasites (tapeworms, amebas, trichinae), such as a cyst" >hydatid cyst.periapical cyst a periodontal cyst involving the apex of an erupted tooth.perineurial cyst an outpouching of the perineurial space on the extradural portion of the posterior sacral or coccygeal nerve roots at the junction of the root and ganglion; it may cause low back pain and sciatica.periodontal cyst one in the periodontal ligament and adjacent structures, usually at the apex of the tooth (cyst" >periapical cyst).pilar cyst a type of cyst" >epidermal cyst, almost always found on the scalp, arising from the outer root sheath of the hair follicle.pilonidal cyst see pilonidal cyst.radicular cyst an epithelium-lined sac at the apex of a tooth.Rathke's c's (Rathke's cleft c's) groups of epithelial cells forming small colloid-filled cysts in the pars intermedia of the pituitary gland; they are vestiges of pouch" >Rathke's pouch and are closely related to craniopharyngiomas.retention cyst a tumorlike accumulation of a secretion formed when the outlet of a secreting gland is obstructed. These cysts may develop in any of the secretory glands, such as the breast, pancreas, kidney, salivary or sebaceous glands, or mucous membranes.sarcosporidian cyst sarcocyst (def. 2).sebaceous cyst see sebaceous cyst.solitary bone cyst a pathologic bone space in the metaphyses of long bones of growing children; it may be either empty or filled with fluid and have a delicate connective tissue lining.subchondral cyst a bone cyst within the fused epiphysis beneath the articular plate.tarry cyst 1. one resulting from hemorrhage into a corpus luteum.2. a bloody cyst resulting from endometriosis.theca-lutein cyst a cyst of the ovary in which the cystic cavity is lined with theca cells.traumatic bone cyst a cavity (not a true cyst) formed in bone, particularly the mandible, in response to trauma. The hematoma precipitated by trauma is resorbed but bone is not replaced; the space formed is usually empty and lacks an epithelial lining.unicameral bone cyst solitary bone cyst.wolffian cyst a cyst of the broad ligament developed from vestiges of the mesonephros.

ap·i·cal per·i·o·don·tal cyst

an inflammatory odontogenic cyst derived histogenetically from Malassez epithelial rests surrounding the root apex of a nonvital tooth. Synonym(s): periapical cyst, radicular cyst, root end cyst

cyst

(sist) [Gr. kystis, bladder, sac] 1. A closed sac or pouch with a definite wall, containing fluid, semifluid, or solid material. It is usually an abnormal structure resulting from developmental anomalies, obstruction of ducts, or parasitic infection. 2. In biology, a structure formed by and enclosing certain organisms in which they become inactive, such as the cyst of certain protozoans or of the metacercariae of flukes.

adventitious cyst

A cyst formed around a foreign body.

alveolar cyst

Dilation and rupture of pulmonary alveoli to form air cysts.

apical cyst

A cyst near the apex of the root of a nonvital tooth.

arachnoid cyst

An abnormal collection of cerebrospinal fluid within the arachnoid membrane. The cysts may compress nearby structures within the brain. In infants, they may cause headaches, altered mental status, learning disabilities, or enlargement of the head. In adults, they are an occasional cause of epilepsy.

Baker cyst

See: Baker cyst.

Bartholin cyst

See: Bartholin, Caspar (the younger)

blood cyst

Hematoma.

blue dome cyst

1. A mammary cyst containing light, straw-colored fluid, which appears blue when seen through the surrounding tissue. 2. A small dark-blue cyst in the vagina caused by retained menstrual blood seen in endometriosis.

branchial cyst

Cervical cyst.

bone cyst

A cystic mass in bone, usually a normal variant or a benign tumor.

Boyer cyst

See: Boyer cyst

cervical cyst

A closed epithelial sac derived from a branchial groove of its corresponding pharyngeal pouch. Synonym: branchial cyst

chocolate cyst

An ovarian cyst with darkly pigmented gelatinous contents.

colloid cyst

A cyst with gelatinous contents.

complex cyst

A cyst that consists of solid material and fluid-filled cavities; it may have walls of tissue inside it or internal echoes. When a complex cyst is identified on ultrasound, surgical removal is generally indicated to exclude malignancy.

congenital cyst

A cyst present at birth and resulting from abnormal development, such as a dermoid cyst, imperfect closure of a structure as in spina bifida cystica, or nonclosure of embryonic clefts, ducts, or tubules, such as cervical cysts.

daughter cyst

A cyst growing out of the walls of another cyst.

dental cyst

A cyst that forms from any of the odontogenic tissues.

dentigerous cyst

A fluid-filled, epithelial-lined cyst usually surrounding the crown of a tooth that is erupting or has not yet erupted. The tooth normally erupts through the cyst without treatment. Synonym: eruption cyst; follicular cyst; follicular odontoma

dermoid cyst

1. An ovarian teratoma. 2. A nonmalignant cystic tumor containing elements derived from the ectoderm, such as hair, teeth, or skin. These tumors occur frequently in the ovary but may develop in other organs such as the lungs.

distention cyst

A cyst formed in a natural enclosed cavity, such as a follicular cyst of the ovary.

echinococcus cyst

Hydatid cyst.

endometrial cyst

An ovarian cyst or tumor lined with endometrial tissue, usually seen in ovarian endometriosis.

epidermoid cyst

A cyst filled with keratin, sebum, and skin debris that may form on the scalp, the back of the neck, or the axilla. It is benign andf can be removed surgically. Synonym: sebaceous cyst

eruption cyst

Dentigerous cyst.

extravasation cyst

A cyst arising from hemorrhage or escape of other body fluids into tissues.

exudation cyst

A cyst caused by trapping of an exudate in a closed area.

FOLLICULAR CYST: Follicular cysts seen on ultrasonography of the thyroid gland.

follicular cyst

A cyst arising from a follicle, as a follicular cyst of the thyroid gland, the ovary, or a forming tooth. Synonym: dentigerous cyst See: illustration

ganglion cyst

ganglion (2)

Gartner cyst

See: Gartner cyst

Gorlin cyst

See: Gorlin cyst

hydatid cyst

A cyst formed by the growth of the larval form of Echinococcus granulosus, usually in the liver. Synonym: echinococcus cyst

implantation cyst

A cyst resulting from displacement of portions of the epidermis, as may occur in injuries.

intraligamentary cyst

A cystic formation between the layers of the broad ligament.

involutional cyst

A cyst occurring in the normal involution of an organ or structure, as in the mammary gland.

keratin cyst

A cyst containing keratin.

cysts of liver

Simple cysts, usually small and single; or hydatid cysts; or cysts associated with cystic disease of the liver, a rare condition usually associated with congenital cystic kidneys. See: Echinococcus granulosus; hydatid

meibomian cyst

Chalazion.

meniscus cyst

A fluid-filled cyst often associated with a degenerative horizontal meniscal tear, more frequently seen in the lateral meniscus of the knee. This ganglion-like cyst may present with a palpable mass at the joint line of the knee and can be visualized by magnetic resonance imaging.

morgagnian cyst

See: Morgagni, Giovanni B

Morgagni cyst

See: Morgagni, Giovanni B

mother cyst

A hydatid cyst enveloping smaller ones.

mucous cyst

A retention cyst composed of mucus.

nabothian cyst

A cyst caused by closure of the ducts of the nabothian glands in the uterine cervix as a result of chronic cervicitis.

odontogenic cyst

A cyst associated with the teeth, such as a dentigerous or radicular cyst.

ovarian cyst

A fluid-filled cyst that develops in the ovary and consists of one or more chambers. The main types of cysts are follicular cysts, the corpus luteum, teratoma, and endometrioma. The patient's primary complaint is generally pelvic pain or pain during intercourse. The cysts may be palpated during bimanual examination but are diagnosed by ultrasound. Many cysts resolve spontaneously. Although nonmalignant, the cyst may have to be removed surgically because of twisting of the pedicle, which causes gangrene, or because of pressure. See: polycystic ovary syndrome

parasitic cyst

A cyst enclosing the larval form of certain parasites, such as the cysticercus or hydatid of tapeworms or the larva of certain nematodes, i.e., Trichinella.

parovarian cyst

A cyst of the parovarium.

periapical cyst

Radicular cyst.

pilar cyst

An epithelial cyst with a wall that resembles the follicular epithelium. It is filled with a homogeneous mixture of keratin and lipid. Synonym: trichilemma cyst

pilonidal cyst

A cyst most often in the sacrococcygeal region, usually at the upper end of the intergluteal cleft. It is due to a developmental defect that permits epithelial tissue to be trapped below the skin or may be acquired. This type of cyst may become symptomatic in early adulthood when an infected draining sinus forms. Synonym: pilonidal fistula

popliteal cyst

Baker cyst.

porencephalic cyst

An anomalous cavity of the brain that communicates with the ventricular system.

proliferative cyst

A cyst lined with epithelium that proliferates, forming projections that extend into the cavity of the cyst.

radicular cyst

A necrotic, inflammatory cyst that develops at the root of a nonvital tooth. The cyst is attached to the root of the tooth and may be lateral to it if the cyst is associated with a lateral pulp canal. Synonym: periapical cyst; root-end cyst

retention cyst

A cyst retaining the secretion of a gland, as in a mucous or sebaceous cyst.

root-end cyst

Radicular cyst.

sebaceous cyst

Epidermoid cyst.

seminal cyst

A cyst of the epididymis, ductus deferens, or other sperm-carrying ducts that contain semen.

suprasellar cyst

A cyst of the hypophyseal stalk just above the floor of the sella turcica. Its wall is frequently calcified or ossified.

synovial cyst

Accumulation of synovia in a bursa, synovial crypt, or sac of a synovial hernia, causing a tumor.

theca-lutein cyst

Benign enlargement of the Graafian follicle, typically occurring in pregnancies (particularly in multiple pregnancies) or in other conditions that cause markedly elevated levels of serum human chorionic gonadotropin (HCG) levels, e.g., molar pregnancies or choriocarcinomas. Synonym: hyperreactio luteinalis

trichilemma cyst

Pilar cyst.

tubo-ovarian cyst

An ovarian cyst that ruptures into the lumen of an adherent uterine tube.

unilocular cyst

A cyst containing only one cavity.

vaginal cyst

A cyst in the vagina.

vitelline cyst

A congenital cyst of the gastrointestinal canal. Lined with ciliated epithelium, it is the remains of the omphalomesenteric duct.

wolffian cyst

A cyst lying in one of the broad ligaments of the uterus.illustration

ap·i·cal per·i·o·don·tal cyst

(ap'i-kăl per'ē-ō-don'tăl sist) Inflammatory odontogenic cyst derived histogenetically from Malassez epithelial rests surrounding root apex of a nonvital tooth.
Synonym(s): periapical cyst, radicular cyst, root end cyst.

单词	periapical cyst
释义	DictionarySeecyst periapical cyst periapical cyst [¦per·ē′ap·ə·kəl ′sist] (medicine) radicular cyst periapical cyst cyst [sist] 1. bladder.2. an abnormal closed epithelium-lined sac in the body that contains a liquid or semisolid substance. Most are harmless, but they should be removed when possible because they occasionally may change into malignant growths, become infected, or obstruct a gland. There are four main types of cysts: retention cysts, exudation cysts, embryonic cysts, and parasitic cysts.3. a stage in the life cycle of certain parasites, during which they are enveloped in a protective wall.adventitious cyst pseudocyst (def. 1).alveolar c's dilatations of pulmonary alveoli, which may fuse by breakdown of their septa to form large air cysts (pneumatoceles).arachnoid cyst a fluid-filled cyst between the layers of the leptomeninges, lined with arachnoid membrane, usually in the sylvian fissure.Baker cyst a swelling on the back of the knee, due to escape of synovial fluid that has become enclosed in a sac of membrane.Bartholin cyst a mucus-filled cyst of a Bartholin gland, usually developing as a consequence of an obstruction of the duct by trauma, infection, epithelial hyperplasia, or congenital atresia or narrowing.Blessig c's cystic spaces formed at the periphery of the retina.blue dome cyst 1. a benign retention cyst of the breast that shows a pale blue color. See also cystic disease of breast.2. a cyst due to endometriosis, found in healed wounds such as those of an episiotomy or an incision for a cesarean section; it is usually found in the vaginal fornix or on the cervix.Boyer cyst an enlargement of the subhyoid bursa.branchial cyst (branchiogenic cyst) (branchiogenous cyst) see branchial cyst.bronchogenic cyst a congenital cyst, usually in the mediastinum or lung, arising from anomalous budding during formation of the tracheobronchial tree, lined with bronchial epithelium that may contain secretory elements.chocolate cyst one filled with hemosiderin, causing a dark color, following local hemorrhage, such as may occur in the ovary in ovarian endometriosis.choledochal cyst a congenital cystic dilatation of the common bile duct, which may cause pain in the right upper quadrant, jaundice, fever, or vomiting, or be asymptomatic.daughter cyst a small parasitic cyst developed from the walls of a larger cyst.dentigerous cyst an cyst" >odontogenic cyst surrounding the crown of a tooth, originating after the crown is completely formed.dermoid cyst see dermoid cyst.duplication cyst a congenital cystic malformation of the alimentary tract, consisting of a duplication of the segment to which it is adjacent, occurring anywhere from the mouth to the anus but most frequently affecting the ileum and esophagus.echinococcus cyst hydatid cyst.embryonic cyst one developing from bits of embryonic tissue that have been overgrown by other tissues, or from developing organs that normally disappear before birth. An example is a branchial cyst.enteric cyst (enterogenous cyst) a cyst of the intestine arising or developing from some fold or pouch along the intestinal tract. Called also enterocyst and enterocystoma.epidermal cyst (epidermoid cyst) an intradermal or subcutaneous cyst containing keratinizing squamous epithelium; it arises from occluded hair follicles. Called also wen.epidermal inclusion cyst a type of cyst" >epidermal cyst occurring on the head, neck, or trunk, formed by keratinizing squamous epithelium with a granular layer.epithelial cyst 1. any cyst lined by keratinizing stratified squamous epithelium, found most often in the skin.2. epidermal cyst.exudation cyst a cyst formed by the slow seepage of an exudate into a closed cavity.false cyst pseudocyst (def. 1).follicular cyst one due to occlusion of the duct of a follicle or small gland, especially one formed by enlargement of a graafian follicle as a result of accumulated transudate.hydatid cyst the larval stage of the tapeworms Echinococcus granulosis and E. multilocularis; each one contains daughter cysts that have many scoleces (mouths). See also hydatid disease. Called also echinococcus cyst and hydatid.inclusion cyst one formed by the inclusion of a small portion of epithelium or mesothelium within connective tissue along a line of fusion of embryonic processes; several types are found in the oral and nasal regions.keratinizing cyst one arising in the pilosebaceous apparatus, lined by stratified squamous epithelium and containing largely macerated keratin and often sufficient sebum to render the contents greasy or rancid.meibomian cyst chalazion.mucus retention cyst a mucus-containing cyst" >retention cyst caused by blockage of a salivary gland duct.multilocular cyst 1. a cyst containing several loculi or spaces.2. a cyst" >hydatid cyst with many small irregular cavities that may contain scoleces but generally little fluid.3. a thick-walled cyst in the kidney, found in clusters and usually unilaterally. In children it contains blastema and may develop into a Wilms tumor.myxoid cyst a nodular lesion usually overlying a distal interphalangeal finger joint in the dorsolateral or dorsomesial position, consisting of focal mucinous degeneration of the collagen of the dermis; not a true cyst, lacking an epithelial wall, it does not communicate with the underlying synovial space.Naboth's c's (nabothian c's) cysts that occur when mucus-producing glands in the columnar epithelium of the uterine cervix become covered over by squamous epithelium resulting from metaplasia; they are usually found in the transformation zone of the cervix. Called also Naboth's or nabothian follicles.nasoalveolar cyst (nasolabial cyst) a fissural cyst arising outside the bones at the junction of the globular portion of the medial nasal process, lateral nasal process, and maxillary process.odontogenic cyst one derived from epithelium, usually containing fluid or semisolid material, which develops during various stages of odontogenesis; nearly always enclosed within bone.parasitic cyst one forming around larval parasites (tapeworms, amebas, trichinae), such as a cyst" >hydatid cyst.periapical cyst a periodontal cyst involving the apex of an erupted tooth.perineurial cyst an outpouching of the perineurial space on the extradural portion of the posterior sacral or coccygeal nerve roots at the junction of the root and ganglion; it may cause low back pain and sciatica.periodontal cyst one in the periodontal ligament and adjacent structures, usually at the apex of the tooth (cyst" >periapical cyst).pilar cyst a type of cyst" >epidermal cyst, almost always found on the scalp, arising from the outer root sheath of the hair follicle.pilonidal cyst see pilonidal cyst.radicular cyst an epithelium-lined sac at the apex of a tooth.Rathke's c's (Rathke's cleft c's) groups of epithelial cells forming small colloid-filled cysts in the pars intermedia of the pituitary gland; they are vestiges of pouch" >Rathke's pouch and are closely related to craniopharyngiomas.retention cyst a tumorlike accumulation of a secretion formed when the outlet of a secreting gland is obstructed. These cysts may develop in any of the secretory glands, such as the breast, pancreas, kidney, salivary or sebaceous glands, or mucous membranes.sarcosporidian cyst sarcocyst (def. 2).sebaceous cyst see sebaceous cyst.solitary bone cyst a pathologic bone space in the metaphyses of long bones of growing children; it may be either empty or filled with fluid and have a delicate connective tissue lining.subchondral cyst a bone cyst within the fused epiphysis beneath the articular plate.tarry cyst 1. one resulting from hemorrhage into a corpus luteum.2. a bloody cyst resulting from endometriosis.theca-lutein cyst a cyst of the ovary in which the cystic cavity is lined with theca cells.traumatic bone cyst a cavity (not a true cyst) formed in bone, particularly the mandible, in response to trauma. The hematoma precipitated by trauma is resorbed but bone is not replaced; the space formed is usually empty and lacks an epithelial lining.unicameral bone cyst solitary bone cyst.wolffian cyst a cyst of the broad ligament developed from vestiges of the mesonephros. ap·i·cal per·i·o·don·tal cyst an inflammatory odontogenic cyst derived histogenetically from Malassez epithelial rests surrounding the root apex of a nonvital tooth. Synonym(s): periapical cyst, radicular cyst, root end cyst cyst (sist) [Gr. kystis, bladder, sac] 1. A closed sac or pouch with a definite wall, containing fluid, semifluid, or solid material. It is usually an abnormal structure resulting from developmental anomalies, obstruction of ducts, or parasitic infection. 2. In biology, a structure formed by and enclosing certain organisms in which they become inactive, such as the cyst of certain protozoans or of the metacercariae of flukes. adventitious cyst A cyst formed around a foreign body. alveolar cyst Dilation and rupture of pulmonary alveoli to form air cysts. apical cyst A cyst near the apex of the root of a nonvital tooth. arachnoid cyst An abnormal collection of cerebrospinal fluid within the arachnoid membrane. The cysts may compress nearby structures within the brain. In infants, they may cause headaches, altered mental status, learning disabilities, or enlargement of the head. In adults, they are an occasional cause of epilepsy. Baker cyst See: Baker cyst. Bartholin cyst See: Bartholin, Caspar (the younger) blood cyst Hematoma. blue dome cyst 1. A mammary cyst containing light, straw-colored fluid, which appears blue when seen through the surrounding tissue. 2. A small dark-blue cyst in the vagina caused by retained menstrual blood seen in endometriosis. branchial cyst Cervical cyst. bone cyst A cystic mass in bone, usually a normal variant or a benign tumor. Boyer cyst See: Boyer cyst cervical cyst A closed epithelial sac derived from a branchial groove of its corresponding pharyngeal pouch. Synonym: branchial cyst chocolate cyst An ovarian cyst with darkly pigmented gelatinous contents. colloid cyst A cyst with gelatinous contents. complex cyst A cyst that consists of solid material and fluid-filled cavities; it may have walls of tissue inside it or internal echoes. When a complex cyst is identified on ultrasound, surgical removal is generally indicated to exclude malignancy. congenital cyst A cyst present at birth and resulting from abnormal development, such as a dermoid cyst, imperfect closure of a structure as in spina bifida cystica, or nonclosure of embryonic clefts, ducts, or tubules, such as cervical cysts. daughter cyst A cyst growing out of the walls of another cyst. dental cyst A cyst that forms from any of the odontogenic tissues. dentigerous cyst A fluid-filled, epithelial-lined cyst usually surrounding the crown of a tooth that is erupting or has not yet erupted. The tooth normally erupts through the cyst without treatment. Synonym: eruption cyst; follicular cyst; follicular odontoma dermoid cyst 1. An ovarian teratoma. 2. A nonmalignant cystic tumor containing elements derived from the ectoderm, such as hair, teeth, or skin. These tumors occur frequently in the ovary but may develop in other organs such as the lungs. distention cyst A cyst formed in a natural enclosed cavity, such as a follicular cyst of the ovary. echinococcus cyst Hydatid cyst. endometrial cyst An ovarian cyst or tumor lined with endometrial tissue, usually seen in ovarian endometriosis. epidermoid cyst A cyst filled with keratin, sebum, and skin debris that may form on the scalp, the back of the neck, or the axilla. It is benign andf can be removed surgically. Synonym: sebaceous cyst eruption cyst Dentigerous cyst. extravasation cyst A cyst arising from hemorrhage or escape of other body fluids into tissues. exudation cyst A cyst caused by trapping of an exudate in a closed area.FOLLICULAR CYST: Follicular cysts seen on ultrasonography of the thyroid gland. follicular cyst A cyst arising from a follicle, as a follicular cyst of the thyroid gland, the ovary, or a forming tooth. Synonym: dentigerous cyst See: illustration ganglion cyst ganglion (2) Gartner cyst See: Gartner cyst Gorlin cyst See: Gorlin cyst hydatid cyst A cyst formed by the growth of the larval form of Echinococcus granulosus, usually in the liver. Synonym: echinococcus cyst implantation cyst A cyst resulting from displacement of portions of the epidermis, as may occur in injuries. intraligamentary cyst A cystic formation between the layers of the broad ligament. involutional cyst A cyst occurring in the normal involution of an organ or structure, as in the mammary gland. keratin cyst A cyst containing keratin. cysts of liver Simple cysts, usually small and single; or hydatid cysts; or cysts associated with cystic disease of the liver, a rare condition usually associated with congenital cystic kidneys. See: Echinococcus granulosus; hydatid meibomian cyst Chalazion. meniscus cyst A fluid-filled cyst often associated with a degenerative horizontal meniscal tear, more frequently seen in the lateral meniscus of the knee. This ganglion-like cyst may present with a palpable mass at the joint line of the knee and can be visualized by magnetic resonance imaging. morgagnian cyst See: Morgagni, Giovanni B Morgagni cyst See: Morgagni, Giovanni B mother cyst A hydatid cyst enveloping smaller ones. mucous cyst A retention cyst composed of mucus. nabothian cyst A cyst caused by closure of the ducts of the nabothian glands in the uterine cervix as a result of chronic cervicitis. odontogenic cyst A cyst associated with the teeth, such as a dentigerous or radicular cyst. ovarian cyst A fluid-filled cyst that develops in the ovary and consists of one or more chambers. The main types of cysts are follicular cysts, the corpus luteum, teratoma, and endometrioma. The patient's primary complaint is generally pelvic pain or pain during intercourse. The cysts may be palpated during bimanual examination but are diagnosed by ultrasound. Many cysts resolve spontaneously. Although nonmalignant, the cyst may have to be removed surgically because of twisting of the pedicle, which causes gangrene, or because of pressure. See: polycystic ovary syndrome parasitic cyst A cyst enclosing the larval form of certain parasites, such as the cysticercus or hydatid of tapeworms or the larva of certain nematodes, i.e., Trichinella. parovarian cyst A cyst of the parovarium. periapical cyst Radicular cyst. pilar cyst An epithelial cyst with a wall that resembles the follicular epithelium. It is filled with a homogeneous mixture of keratin and lipid. Synonym: trichilemma cyst pilonidal cyst A cyst most often in the sacrococcygeal region, usually at the upper end of the intergluteal cleft. It is due to a developmental defect that permits epithelial tissue to be trapped below the skin or may be acquired. This type of cyst may become symptomatic in early adulthood when an infected draining sinus forms. Synonym: pilonidal fistula popliteal cyst Baker cyst. porencephalic cyst An anomalous cavity of the brain that communicates with the ventricular system. proliferative cyst A cyst lined with epithelium that proliferates, forming projections that extend into the cavity of the cyst. radicular cyst A necrotic, inflammatory cyst that develops at the root of a nonvital tooth. The cyst is attached to the root of the tooth and may be lateral to it if the cyst is associated with a lateral pulp canal. Synonym: periapical cyst; root-end cyst retention cyst A cyst retaining the secretion of a gland, as in a mucous or sebaceous cyst. root-end cyst Radicular cyst. sebaceous cyst Epidermoid cyst. seminal cyst A cyst of the epididymis, ductus deferens, or other sperm-carrying ducts that contain semen. suprasellar cyst A cyst of the hypophyseal stalk just above the floor of the sella turcica. Its wall is frequently calcified or ossified. synovial cyst Accumulation of synovia in a bursa, synovial crypt, or sac of a synovial hernia, causing a tumor. theca-lutein cyst Benign enlargement of the Graafian follicle, typically occurring in pregnancies (particularly in multiple pregnancies) or in other conditions that cause markedly elevated levels of serum human chorionic gonadotropin (HCG) levels, e.g., molar pregnancies or choriocarcinomas. Synonym: hyperreactio luteinalis trichilemma cyst Pilar cyst. tubo-ovarian cyst An ovarian cyst that ruptures into the lumen of an adherent uterine tube. unilocular cyst A cyst containing only one cavity. vaginal cyst A cyst in the vagina. vitelline cyst A congenital cyst of the gastrointestinal canal. Lined with ciliated epithelium, it is the remains of the omphalomesenteric duct. wolffian cyst A cyst lying in one of the broad ligaments of the uterus.illustration ap·i·cal per·i·o·don·tal cyst (ap'i-kăl per'ē-ō-don'tăl sist) Inflammatory odontogenic cyst derived histogenetically from Malassez epithelial rests surrounding root apex of a nonvital tooth. Synonym(s): periapical cyst, radicular cyst, root end cyst.
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