- : A closed sac or capsule, usually filled with fluid or semisolid material.
* * *1. A bladder. 2. An abnormal sac containing gas, fluid, or a semisolid material, with a membranous lining. SEE ALSO: pseudocyst. [G. kystis, bladder]- alveolar hydatid c. a hydatid c. of a multiloculate type, usually in the liver, caused by Echinococcus multilocularis, adults of which are in foxes; larvae (alveolar hydatid) are found chiefly in microtine rodents, but also among humans such as trappers and others handling pelts of infected foxes and other carnivores; growth is by exogenous budding and is not limited by an outer laminated membrane as in the hydatid c. from E. granulosus; necrosis, cavitation, contiguous spread, and death usually ensue. SYN: multilocular hydatid c., multiloculate hydatid c..- aneurysmal bone c. a solitary benign osteolytic lesion expanding a long bone or within a vertebra, consisting of blood-filled spaces, and separated by fibrous tissue containing multinucleated giant cells; may cause swelling, pain, and tenderness and compromise the structural integrity of the involved bone.- apical periodontal c. an inflammatory odontogenic c. derived histogenetically from Malassez epithelial rests surrounding the root apex of a nonvital tooth. SYN: periapical c., radicular c., root end c..- arachnoid c. a fluid-filled c. lined with arachnoid membrane, frequently situated near the lateral aspect of the fissure of Sylvius; usually congenital in origin. SYN: leptomeningeal c..- Baker c. a collection of synovial fluid which has escaped from the knee joint or a bursa and formed a new synovial-fluid lined sac in the popliteal space; seen in degenerative or other joint diseases that produce increased amounts of synovial fluid.- blue dome c. 1. one of a number of small dark blue nodules or cysts in the vaginal fornix due to retained menstrual blood in endometriosis affecting this region; 2. a benign retention c. of the mammary gland in fibrocystic disease, containing a pale slightly yellow fluid which gives a blue color to the c. when seen through the surrounding fibrous tissue.- botryoid odontogenic c. a type of lateral periodontal c. that shows a multilocular growth pattern.- Boyer c. a subhyoid c..- branchial c. a cervical c. arising from developmental persistence of ectodermal branchial grooves or endodermal pharyngeal pouches. SYN: branchial cleft c..- bronchogenic c. a c. lined by ciliated columnar epithelium believed to represent bronchial differentiation; smooth muscle and mucous glands may be present.- calcifying and keratinizing odontogenic c. SYN: calcifying odontogenic c..- calcifying odontogenic c. a mixed radiolucent-radiopaque lesion of the jaws with features of both a c. and a solid neoplasm; characterized microscopically by an epithelial lining showing a palisaded layer of columnar basal cells, presence of ghost cell keratinization, dentinoid, and calcification. SYN: calcifying and keratinizing odontogenic c., Gorlin c..- cerebellar c. a c. usually occurring in the lateral cerebellar white matter; often a part of cerebellar astrocytoma.- chocolate c. c. of the ovary with intracavitary hemorrhage and formation of a hematoma containing old brown blood; often seen with endometriosis of the ovary but occasionally with other types of cysts.- choledochal c. c. originating from common bile duct; usually becomes apparent early in life as a right upper abdominal mass in association with jaundice.- dentigerous c. an odontogenic c. derived from the reduced enamel epithelium surrounding the crown of an impacted or embedded tooth. SYN: follicular c. (2).- dermoid c. a tumor consisting of displaced ectodermal structures along lines of embryonic fusion, the wall being formed of epithelium-lined connective tissue, including skin appendages and containing keratin, sebum, and hair. SYN: dermoid tumor, dermoid (2).- dermoid c. of ovary a common benign cystic teratoma of the ovary, lined for the most part by skin, and containing hair and sebum, but also usually containing a variety of other well differentiated structures within a small inwardly projecting mass of solid tissue.- duplication c. a congenital cystic malformation attached to or originating from any part of the alimentary canal, from the base of the tongue to the anus, which reproduces the structure of the adjacent alimentary tract.- echinococcus c. SYN: hydatid c..- endometrial c. a c. resulting from endometrial implantation outside the uterus, as in endometriosis.- enterogenous c. mediastinal c. derived from cells sequestered from the primitive foregut; may be classified histologically as bronchogenic, esophageal, or gastric.- ependymal c. a circumscribed distention of some portion of the central canal of the spinal cord or of the cerebral ventricles. SYN: neural c..- epidermal c. a c. formed of a mass of epidermal cells which, as a result of trauma, has been pushed beneath the epidermis; the c. is lined with stratified squamous epithelium and contains concentric layers of keratin. SYN: implantation c., inclusion c. (1), inclusion dermoid.- epidermoid c. a spherical, unilocular c. of the dermis, comprised of encysted keratin and sebum; the c. is lined by a keratinizing epithelium resembling the epidermis derived from the follicular infundibulum.- eruption c. a form of dentigerous c. in the soft tissues in conjunction with an erupting tooth; seen on the alveolar ridge of children.- exudation c. a c. resulting from distention of a closed cavity, such as a bursa, by an excessive secretion of its normal fluid contents.- false c. SYN: pseudocyst (1).- fissural c. a c. derived from epithelial remnants entrapped along the fusion line of embryonal processes. SYN: inclusion c. (2).- Gartner c. a c. of the principal duct in the vestigial structures of the paroöphoron in the cervix or anterolateral vaginal wall, corresponding to the sexual portion of mesonephros in the male.- gingival c. a c. derived from remnants of the dental lamina situated in the attached gingiva, occasionally producing superficial erosion of the cortical plate of bone; most are located in the cuspid-premolar region.- globulomaxillary c. (glo′boo-lo-maks′il-lar-e) a c. of odontogenic origin found between the roots of the maxillary lateral incisor and canine teeth.- glomerular c. c. formed by dilation of Bowman capsule, found in rare cases of congenital polycystic kidneys.- Gorlin c. SYN: calcifying odontogenic c..- granddaughter c. a tertiary c. sometimes developed within a daughter c., as in the hydatid c. of Echinococcus.- hemorrhagic c. a c. containing blood or resulting from the encapsulation of a hematoma. SYN: blood c., hematocele (1), hematocyst, sanguineous c..- hepatic c. congenital c. thought to originate from an obstruction of biliary ductules; may be solitary and range in size from small to enormous; polycystic disease may also occur.- heterotrophic oral gastrointestinal c. a c. of the oral cavity lined by gastric or intestinal mucosa from misplaced embryonic rests.- hydatid c. a c. formed in the liver, or, less frequently, elsewhere, by the larval stage of Echinococcus, chiefly in ruminants; two morphologic forms caused by Echinococcus granulosus are found in humans: the unilocular hydatid c. and the osseous hydatid c.; a third form in humans is the alveolar hydatid c., caused by Echinococcus multilocularis. SYN: echinococcus c., hydatid (1).- implantation c. SYN: epidermal c..- incisive canal c. a c. in or near the incisive canal, arising from proliferation of epithelial remnants of the nasopalatine duct; the most common maxillary development c.. SYN: median anterior maxillary c., nasopalatine duct c..- junctional c. a c. of the testis arising from the structures connecting the rete testis with the epididymis.- Klestadt c. SYN: nasoalveolar c..- lacteal c. a retention c. in the mammary gland resulting from closure of a lactiferous duct. SYN: milk c..- lateral periodontal c. an intraosseous c., usually encountered in the cuspid-premolar region of the mandible, derived from the remnants of the dental lamina and representing the intraosseous counterpart of the gingival c..- lymphoepithelial c. a cervical c. arising from salivary gland epithelium entrapped in lymph node s during embryogenesis. Also seen within the oral cavity.- median raphe c. of the penis a c. of the raphe penis resulting from incomplete closure of the urethral groove, becoming clinically evident in childhood or later.- mother c. a hydatid c. from the inner, or germinal, layer, from which secondary cysts containing scoleces (daughter cysts) are developed; sometimes tertiary cysts (granddaughter cysts) are developed within the daughter cysts; occurs most frequently in the liver, but may be found in other organs and tissues; symptoms are those of a tumor of the part affected. SYN: parent c..- mucous c. a retention c. resulting from obstruction in the duct of a mucous gland. SYN: mucocele (1).- multilocular c. a c. containing several compartments formed by membranous septa. SYN: compound c..- nabothian c. a retention c. that develops when a mucous gland of the cervix uteri is obstructed; of no pathologic significance. SYN: nabothian follicle.- nasoalveolar c. a soft tissue c. located near the attachment of the ala over the maxilla; probably derived from the lower anterior part of the nasolacrimal duct. SYN: Klestadt c., nasolabial c..- nasolabial c. SYN: nasoalveolar c..- necrotic c. a c. due to a circumscribed encapsulated area of necrosis with subsequent liquefaction of the dead tissue.- neurenteric cysts paravertebral cysts commonly connected to the meninges or a portion of the gastrointestinal tract that develop due to incomplete separation of endoderm from the notochord during early fetal life; often symptomatic.- odontogenic c. a c. derived from odontogenic epithelium. [odont- + G. genos, birth, origin, + suffix -ic, pertaining to]- oil c. a c. resulting from loss of the epithelial lining of a sebaceous, dermoid, or lacteal c., or from the subcutaneous injection of oil or fat material.- omphalomesenteric c. cystic lesion found within the umbilical cord, presumed to develop from remnants of the omphalomesenteric duct early in gestation. May be found on antenatal ultrasound. SYN: omphalomesenteric duct c..- oophoritic c. SYN: ovarian c..- osseous hydatid c. a morphologic form of hydatid c. caused by Echinococcus granulosus, and found in the long bones or the pelvic arch of humans if the embryo is filtered out in bony tissue; in this site no limiting membrane forms and the c. grows in an uncontrolled fashion, producing cancellous structures and inducing fracture, followed by spread to new sites.- ovarian c. a cystic tumor of the ovary, either non-neoplastic (follicle, lutein, germinal inclusion, or endometrial) or neoplastic; usually restricted to benign cysts, i.e., mucinous serous cystadenoma, or dermoid cysts. SYN: oophoritic c..- paraphysial cysts cysts arising from vestigial remnants of the paraphysis; they are the possible origin of some third ventricular colloid cysts.- paroophoritic c. a c. arising from the paroöpheron.- pearl c. a mass of epithelial cells introduced into the interior of the eye by a perforating injury.- phaeomycotic c. a subcutaneous cystic granuloma caused by pigmented fungi, usually solitary and located on the extremities.- pilar c. a common c. of the skin, especially the scalp, which contains sebum and keratin, and is lined by pale-staining stratified epithelial cells derived from follicular trichilemma. SYN: sebaceous c., trichilemmal c..- posttraumatic leptomeningeal c. a persistent cystic accumulation of cerebrospinal fluid with progressive loss of bone and dura, occurring at the site of a previous fracture.- primordial c. a c. that develops in place of a tooth through cystic degeneration of the enamel organ before formation of calcified odontogenic tissue.- proliferating tricholemmal c. SYN: pilar tumor of scalp.- proliferation c., proliferative c., proliferous c. a mother c. containing daughter cysts; a c. with tumorous formation at one portion of the sac.- protozoan c. infectious form of many protozoan parasites such as Entamoeba histolytica, Giardia lamblia, Balantidium coli, usually passed in the feces and provided with a highly condensed cytoplasm and resistant cell wall.- pseudomucinous c. a c. containing a gelatinous fluid, formerly thought to differ significantly from mucin, occurring especially in the ovary.- Rathke cleft c. an intrasellar or suprasellar c. lined by cuboidal epithelium derived from remnants of Rathke pouch.- retention c. a c. resulting from some obstruction to the excretory duct of a gland. SYN: distention c., secretory c..- sebaceous c. SYN: pilar c..- sequestration c.- solitary bone c. a unilocular c. containing serous fluid and lined with a thin layer of connective tissue, occurring usually in the shaft of a long bone in a child. SYN: idiopathic bone cavity, osteocystoma, simple bone c., traumatic bone c., unicameral bone c..- sudoriferous c. a c. caused by a blocked excretory duct of Moll glands, under gland. SYN: apocrine hidrocystoma.- surgical ciliated c. a c. that arises from maxillary sinus epithelium implanted along a line of surgical entry.- Tarlov c. a perineural c. found in the proximal radicles of the lower spinal cord; it is usually productive of symptoms.- tarry c. a c. or collection of old blood having a tarry or black, sticky appearance; usually due to endometriosis.- teratomatous c. a c. containing structures derived from all three of the primary germ layers of the embryo.- thyroglossal duct c., thyrolingual c. a c. in the midline of the neck resulting from nonclosure of a segment of the ductus thyroglossus.- Tornwaldt c. inflammation or obstruction of the pharyngeal bursa or an adenoid cleft with the formation of a c. containing pus. SYN: Tornwaldt disease.- trichilemmal c. SYN: pilar c..- umbilical c. SYN: vitellointestinal c..- unicameral c. SYN: unilocular c..- unilocular c. a c. having a single sac. SYN: unicameral c..- unilocular hydatid c. the commonest form of hydatid c. in man, caused by Echinococcus granulosus and found in the liver, lungs, or any other site where the hexacanth embryo may settle if it passes the hepatic or pulmonary capillary filters; characterized by large balloonlike forms lined internally with a germinative membrane, enclosed externally in a laminated membrane within a host-parasite capsule, and filled with fluid (hydatid fluid) and infectious scoleces of the young tapeworms (hydatid sand).- urachal c. a c. of the urachus which may communicate with the umbilicus or bladder, or give rise to a midline swelling. SYN: allantoic c..- vitellointestinal c. a small red sessile or pedunculated tumor at the umbilicus in an infant; it is due to the persistence of a segment of the vitellointestinal duct. SYN: umbilical c..- wolffian c. a c. lying in the broad ligaments of the uterus and arising from any mesonephric structures.
* * *cyst 'sist n1) a closed sac having a distinct membrane and developing abnormally in a body cavity or structure2) a body resembling a cyst: asa) a capsule formed about a minute organism going into a resting or spore stage also this capsule with its contentsb) a resistant cover about a parasite produced by the parasite or the host compare HYDATID (2a)
* * *n.1. an abnormal sac or closed cavity lined with epithelium and filled with liquid or semisolid matter. There are many varieties of cysts occurring in different parts of the body. Retention cysts arise when the outlet of a glandular duct is blocked, as in sebaceous cyst. Some cysts are congenital, due to abnormal embryonic development; for example, dermoid cyst. Others are tumours containing cells that secrete mucus or other substances, and another type of cyst is formed by parasites in the body (see hydatid). Cysts may occur in the jaws: a dental cyst occurs at the apex of a tooth, a dentigerous cyst occurs around the crown of an unerupted tooth, and an eruption cyst forms over an erupting tooth. See also fimbrial cyst, ovarian cyst.2. a dormant stage produced during the life cycle of certain protozoan parasites of the alimentary canal, including Giardia and Entamoeba. Cysts, passed out in the faeces, have tough outer coats that protect the parasites from unfavourable conditions. The parasites emerge from their cysts when they are eaten by a new host.3. a structure formed by and surrounding the larvae of certain parasitic worms.
* * *(sist) [Gr. kystis sac, bladder] 1. an abnormal closed cavity in the body, lined by epithelium and containing a liquid or semisolid material. Some cavities that are not lined by epithelium and should properly be called pseudocysts are commonly referred to as cysts; see pseudocyst. 2. a stage in the life cycle of certain parasites, during which they are enclosed within a protective wall; see, for example, hydatid c., multilocular c. (def. 2) and pseudocyst (def. 2). 3. vesica.
Medical dictionary. 2011.