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Medical Dictionary


cyclodiathermy (si′klo-di-a-ther′me)
Diathermy applied to the sclera adjacent to the ciliary body in the treatment of glaucoma.

cycloduction (si-klo-duk′shun)
Rotation of the eye around its visual axis. SYN: circumduction (2) [TA] , cyclotorsion. [cyclo- + L. duco, pp. ductus, to draw]

cycloguanil pamoate (si-klo-gwahn′il)
A long-acting antimalarial agent that prevents the growth or survival of the pre-erythrocytic and erythrocytic parasites.

cyclohexanesulfamic acid (si-klo-heks′an-sul-fam′ik)
SYN: cyclamic acid.

cycloheximide (si-klo-heks′i-mid)
An antibiotic obtained from certain strains of Streptomyces griseus; used in biochemical research to inhibit in vitro protein synthesis; also a fungicide and rat repellent.

cyclohexylsulfamic acid (si-klo-hek′sil-sul-fam′ik)
SYN: cyclamic acid.

cycloid (si′kloyd)
Suggesting cyclothymia; a term applied to a person who tends to have periods of marked swings of mood, but within normal limits. [cyclo- + G. eidos, resembling]

cyclol (si′klol)
A cyclic dipeptide postulated as occurring in proteins; it does occur in some of the ergot alkaloids.

cyclonamine (si-klo-na′men)
SYN: ethamsylate.

cyclooxygenase (si′klo-oks′e-jen-as)
SYN: prostaglandin endoperoxide synthase.

cyclopea (si-klo′pe-a)
SYN: cyclopia.

cyclopean (si-klo′pe-an)
SYN: cyclopian.

cyclopentamine hydrochloride (si-klo-pent′a-men)
A sympathomimetic amine, similar in action to ephedrine.

cyclopentane (si-klo-pen′tan)
A closed ring hydrocarbon containing five carbon atoms, isomeric with pentene.

cyclopenta[a]phenanthrene (si-klo-pen-ta[a]fen′a-thren)
Phenanthrene, to the a side of which a three-carbon fragment is fused; as the perhydro (saturated) derivative, it is the basic structure of the steroids.

cyclopenthiazide (si′klo-pen-thi′a-zid)
A benzothiadiazide diuretic.

cyclopentolate hydrochloride (si-klo-pen′to-lat)
An anticholinergic, spasmolytic drug, used in refraction determinations; causes cycloplegia and mydriasis; an atropinelike agent with brief duration of action.

cyclopeptide (si-klo-pep′tid)
A polypeptide lacking terminal &cbond;NH2 and &cbond;COOH groups by virtue of their combination to form another peptide link, forming a ring.

cyclophenazine hydrochloride (si-klo-fen′a-zen)
A tranquilizing drug.

cyclophorases (si-klo-for′as-ez)
The group of enzymes in mitochondria that catalyze the complete oxidation of pyruvic acid to carbon dioxide and water; essentially, those enzymes and coenzymes involved in the tricarboxylic acid cycle.

cyclophoria (si-klo-fo′re-a)
Abnormal tendency for each eye to rotate around its anteroposterior axis, the rotation being prevented by visual fusional impulses. [cyclo- + G. phora, movement]

cyclophosphamide (si-klo-fos′fa-mid)
An alkylating agent with antitumor activity and uses similar to those of its parent compound, nitrogen mustard (mechlorethamine hydrochloride); also a suppressor of B-cell activity and antibody formation, used to treat autoimmune diseases.

cyclophotocoagulation (si′klo-fo′to-ko-ag-u-la′shun)
Photocoagulation of the ciliary processes to reduce the secretion of aqueous humor in glaucoma. [cyclo- + photocoagulation]

Cyclophyllidae (si-klo-fil′i-de)
An order of tapeworms that includes most of the common parasites of humans and domestic animals. [cyclo- + G. phyllon, leaf]

cyclopia (si-klo′pe-a)
A congenital defect in which the two orbits are united to form a single cavity containing one eye, which typically results from union of the right and left optic primordia, usually combined with holoprosencephaly or cyclencephaly. SYN: cyclopea, synophthalmia, synophthalmus. [G. Kyklops, fr. kyklos, circle, + ops, eye]

cyclopian (si-klo′pe-an)
Denoting or relating to cyclopia. SYN: cyclopean.

cycloplegia (si-klo-ple′je-a)
Loss of power in the ciliary muscle of the eye; may be by denervation or by pharmacologic action. [cyclo- + G. plege, stroke]

cycloplegic (si-klo-ple′jik)
1. Relating to cycloplegia. 2. A drug that paralyzes the ciliary muscle and thus the power of accommodation.

cyclopropane (si-klo-pro′pan)
An explosive gas of characteristic odor; in the past, widely used for producing general anesthesia. SYN: trimethylene.

cyclops (si′klops)
An individual with cyclopia. SYN: monoculus (1) , monophthalmus, monops. [see cyclopia]

cycloserine (si-klo-ser′en)
An antibiotic produced by strains of Streptomyces orchidaceus or S. garyphalus with a wide spectrum of antibacterial activity. SYN: orientomycin.

cyclosis (si-klo′sis)
The movement of the protoplasm and contained plastids within the protozoan cell. [G., fr. kykloo, to move around]

Cyclospora (si-klo-spor′ah)
A Cryptosporidium-like genus of coccidian parasites reported from millipedes, reptiles, insectivores, and a rodent species. C. is characterized by acid-fast oocysts with two sporocysts, each with two sporozoites. C. is implicated as the cause of a widespread, prolonged but self-limited human diarrhea in patients in the Americas, Caribbean countries, Southeast Asia, and eastern Europe previously reported as caused by cyanobacteriumlike bodies. SYN: cyanobacteriumlike bodies. C. cayetanensis a species causing enteritis with persistent diarrhea; usually acquired by ingestion of contaminated water or food.

cyclosporin A (si-klo-spor′in)
SYN: cyclosporine.

cyclosporine (si-klo-spor′en)
A cyclic oligopeptide immunosuppressant produced by the fungus Tolypocladium inflatum Gams; used to inhibit organ transplant rejection. SYN: cyclosporin A.

cyclothiazide (si-klo-thi′a-zid)
A diuretic and antihypertensive.

cyclothymia (si-klo-thi′me-a)
A mental disorder characterized by marked swings of mood from depression to hypomania but not to the degree that occurs in bipolar disorder. SYN: cyclothymic disorder. [cyclo- + G. thymos, rage]

cyclothymiac, cyclothymic (si-klo-thi′me-ak, -thi′mik)
Relating to cyclothymia.

cyclotomy (si-klot′o-me)
Operation of cutting the ciliary muscle. [cyclo- + G. tome, incision]

cyclotorsion (si′klo-tor′shun)
SYN: cycloduction.

cyclotron (si′klo-tron)
An accelerator that produces high-speed ions ( e.g., protons and deuterons) under the influence of an alternating magnetic field, for bombardment and disruption of atomic nuclei. Used to produce clinically useful positron-emitting radionuclides. [cyclo- + G. -tron, instrumental suffix]

cyclotropia (si-klo-tro′pe-a)
A disparity of ocular position in which one eye is rotated around its visual axis, with respect to the other eye. [cyclo- + G. trope, a turn, turning]

cyclozoonosis (si′klo-zo-o-no′sis)
A zoonosis that requires more than one vertebrate host (but no invertebrate) for completion of the life cycle; e.g., various taenioid cestodes such as Taenia saginata and T. solium in which humans are an obligatory host; hydatid disease, a c. in which humans are not obligatory host. [cyclo- + G. zoon, animal, + nosos, disease]

Symbol for cytidine.

cyesis (si-e′sis)
Obsolete term for pregnancy. [G. kyesis]

Abbreviation for cylinder, or cylindrical lens.

cylinder (cyl., C) (sil′in-der)
1. A cylindrical lens. 2. A cylindrical or rodlike renal cast. 3. A cylindrical metal container for gases stored under high pressure. [G. kylindros, a roll] Bence Jones cylinders slightly irregular, relatively smooth, rod-shaped or cylindroid bodies of fairly tenacious, viscid proteinaceous material in the fluid of the seminal vesicles. crossed cylinders a lens used in refraction to determine the strength and axis of a cylindrical lens to correct astigmatism; a combination of concave and convex cylinders of like power whose axes are at right angles to each other. Külz c. SYN: coma cast.

cylindraxis (sil-in-drak′sis)
Historical precursor of the term axon, based on an interpretation of the myelinated nerve fiber as a cylinder of which the axon formed the axis.

cylindrical (si-lin′dri-kal)
Shaped like a cylinder; referring to a cylinder.

cylindroadenoma (sil′in-dro-ad-e-no′ma)
SYN: cylindroma.

cylindroid (sil′in-droyd)
SYN: false cast. [G. kylindrodes, fr. kylindros, roll, cylinder, + eidos, appearance]

cylindroma (sil-in-dro′ma)
A histologic type of epithelial neoplasm, frequently malignant, characterized by islands of neoplastic cells embedded in a hyalinized stroma which may represent a thickened basement membrane; may form from ducts of glands, especially in salivary glands, skin, and bronchi; in the salivary glands, also termed adenoid cystic carcinoma. SYN: cylindroadenoma. [G. kylindros, cylinder, -oma, tumor]

cylindruria (sil-in-droo′re-a)
The presence of renal cylinders or casts in the urine.

cyllosoma (sil-o-so′ma)
One-sided congenital defect of the lower abdominal wall (eventration) with defective development of the corresponding lower limb. [G. kyllos, deformed, esp. clubfooted or bandylegged, + soma, body]

cymarin (si′ma-rin)
K-Strophanthin-α, a glycoside of cymarose present in the seeds of Strophanthus kombé; the aglycone is strophanthin; a cardiotonic.

cymba conchae (sim′ba kong′ke) [TA]
The upper, smaller part of the external ear lying above the crus helicis. [G. kymbe, the hollow of a vessel, a cup, bowl, a boat]

cymbocephalic, cymbocephalous (sim-bo-se-fal′ik, -sef′a-lus)
Relating to cymbocephaly.

cymbocephaly (sim-bo-sef′a-le)
SYN: scaphocephaly. [G. kymbe, the hollow of a vessel, a boat-shaped structure, + kephale, head]

cynanthropy (si-nan′thro-pe)
A delusion in which one barks and growls, imagining oneself to be a dog. [G. kyon, dog, + anthropos, man]

cynocephaly (si-no-sef′a-le)
Craniostenosis in which the skull slopes back from the orbits, producing a resemblance to the head of a dog. [G. kyon, dog, + kephale, head]

cynodont (si′no-dont)
1. A canine tooth. 2. A tooth having one cusp or point. [G. kyon, dog, + odous (odont-), tooth]

cynophobia (si-no-fo′be-a)
Morbid fear of dogs. [G. kyon, dog, + phobos, fear]

Elie de, Russian physiologist, 1843–1912. See C. nerve.

Abbreviation for cytochrome P450 enzymes; usually followed by an arabic numeral, a letter, and another arabic numeral ( e.g., C. 2D6). These enzymes are found in and on the smooth endoplasmic reticulum of liver and other cells and are responsible for a large number of drug biotransformation reactions. C. 1A2 microsomal enzyme, the substrates of which include theophylline, antidepressants, and tacrine. It is inhibited by grapefruit juice and quinolones, and induced by smoking, phenobarbital, phenytoin, rifampin, and omeprazole. C. 2C9 microsomal enzyme responsible for the oxidation of S-warfarin, phenytoin, and numerous NSAIDs. Inhibitors include azole antifungals ( e.g., ketoconazole, itraconazole, metronidazole); induced by rifampin. C. 2C19 microsomal enzyme partially responsible for the oxidation of clomipramine, diazepam, propranolol, imipramine, and omeprazole. Inhibited by fluoxetine, sertraline, omeprazole, and ritinovir. C. 2D6 the isoenzyme that metabolizes many antidepressants, antipsychotic agents, beta adrenergic blockers, and codeine. It is inhibited by cimetidine and several antidepressants and antipsychotics. C. 2E1 microsomal enzyme that participates in the oxidation of ethanol and acetaminophen. Inhibited by disulfiram and induced by ethanol and isoniazid (INH). Believed to be responsible for the hepatotoxic metabolite of acetaminophen. C. 3A a cytochrome P450 isoform found in the gastrointestinal tract as well as hepatic and other cells; substrates include benzodiazepines, calcium channel blockers, antihistamines, steroid hormones, and protease inhibitors. Inhibited by antidepressants, azole antifungals, cimetidine, and erythromycin. Induced by phenobarbital, phenytoin, rifampin, and carbamazepine.

cypridophobia (si′pri-do-fo′be-a)
Morbid fear of venereal disease or of sexual intercourse. [G. Kypris, Aphrodite, + phobos, fear]

cyproheptadine hydrochloride (si-pro-hep′ta-den)
A potent antagonist of histamine and serotonin, with H1 antihistaminic and antipruritic actions.

cyproterone acetate (si-pro′ter-on)
A synthetic steroid capable of inhibiting the biological effects exerted by endogenous or exogenous androgenic hormones; an antiandrogen.

Symbol for cysteine (half-cystine) or its mono- or diradical.

cyst (sist)
1. A bladder. 2. An abnormal sac containing gas, fluid, or a semisolid material, with a membranous lining. SEE ALSO: pseudocyst. [G. kystis, bladder] adventitious c. SYN: pseudocyst (1) . allantoic c. SYN: urachal c.. 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. angioblastic c. mesenchymal tissue capable of forming blood in the embryo. 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.. apoplectic c. a pseudocyst formed of extravasated blood as in a stroke. 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. Bartholin c. a c. arising from the major vestibular gland or its ducts. bile c. SYN: gallbladder. blood c. SYN: hemorrhagic c.. 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. bone c. solitary bone c.. 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.. branchial cleft c. SYN: branchial c.. bronchogenic c. a c. lined by ciliated columnar epithelium believed to represent bronchial differentiation; smooth muscle and mucous glands may be present. bursal c. a retention c. in a bursa. 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. chyle c. a circumscribed dilation of a lymphatic channel of the mesentery, containing chyle. colloid c. a c. with gelatinous contents. compound c. SYN: multilocular c.. corpora lutea c. persistent corpora lutea with c. formation. Cowper c. a retention c. of a bulbourethral gland. daughter c. a secondary c., usually multiple, derived from a mother c.. 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. distention c. SYN: retention c.. 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.. endodermal c. c. lined by columnar epithelium; presumed dermal in origin. endometrial c. a c. resulting from endometrial implantation outside the uterus, as in endometriosis. endothelial c. a serous c. whose sac is lined with endothelium. 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. epithelial c. a c. lined with epithelium. eruption c. a form of dentigerous c. in the soft tissues in conjunction with an erupting tooth; seen on the alveolar ridge of children. extravasation c. obsolete term for hemorrhagic c.. 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) . follicular c. 1. a cystic graafian follicle; 2. SYN: dentigerous c.. 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. gas c. a c. with gaseous instead of the ordinary liquid or pultaceous contents. 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.. inclusion c. 1. SYN: epidermal c.. 2. SYN: fissural c.. junctional c. a c. of the testis arising from the structures connecting the rete testis with the epididymis. keratinous c. an epithelial c. containing keratin. 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.. leptomeningeal c. SYN: arachnoid c.. lymphoepithelial c. a cervical c. arising from salivary gland epithelium entrapped in lymph nodes during embryogenesis. Also seen within the oral cavity. median anterior maxillary c. SYN: incisive canal c.. median palatal c. a developmental c. located in the midline of the hard palate. 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. meibomian c. SYN: chalazion. milk c. SYN: lacteal c.. morgagnian c. SYN: vesicular appendages of epoophoron, under appendage. 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.. multilocular hydatid c., multiloculate hydatid c. SYN: alveolar hydatid c.. myxoid c. SYN: ganglion (2) . 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.. nasopalatine duct c. SYN: incisive canal c.. necrotic c. a c. due to a circumscribed encapsulated area of necrosis with subsequent liquefaction of the dead tissue. neural c. SYN: ependymal c.. 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.. omphalomesenteric duct c. SYN: omphalomesenteric 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. parasitic c. a c. formed by the larva of a metazoan parasite, such as a hydatid or trichinal c.. parent c. SYN: mother c.. paroophoritic c. a c. arising from the paroöpheron. parvilocular c. a tumor composed of multiple small cysts. pearl c. a mass of epithelial cells introduced into the interior of the eye by a perforating injury. periapical c. SYN: apical periodontal c.. 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.. piliferous c. a dermoid c. containing hair. pilonidal c. pilonidal sinus. pineal c. a c. of the pineal gland; rarely of clinical importance. 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. radicular c. SYN: apical periodontal c.. Rathke cleft c. an intrasellar or suprasellar c. lined by cuboidal epithelium derived from remnants of Rathke pouch. residual c. the persistence of an apical periodontal c. that remains after tooth extraction. retention c. a c. resulting from some obstruction to the excretory duct of a gland. SYN: distention c., secretory c.. rete c. of ovary a c. derived from the germinal cords in the hilum of the ovary. root end c. SYN: apical periodontal c.. sanguineous c. SYN: hemorrhagic c.. sebaceous c. SYN: pilar c.. secretory c. SYN: retention c.. seminal vesical c. a c., usually congenital, of the seminal vesicle. sequestration c. serous c. a c. containing clear serous fluid, such as a hygroma. simple bone c. SYN: solitary bone 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.. Stafne bone c. SYN: lingual salivary gland depression. static bone c. SYN: lingual salivary gland depression. sterile c. a hydatid c. without brood capsules or viable scoleces. sublingual c. SYN: ranula (2) . sudoriferous c. a c. caused by a blocked excretory duct of Moll glands, under gland. SYN: apocrine hidrocystoma. suprasellar c. SYN: craniopharyngioma. surgical ciliated c. a c. that arises from maxillary sinus epithelium implanted along a line of surgical entry. synovial c. SYN: ganglion (2) . 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. tarsal c. SYN: chalazion. 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. traumatic bone c. SYN: solitary bone c.. trichilemmal c. SYN: pilar c.. tubular c. SYN: tubulocyst. umbilical c. SYN: vitellointestinal c.. unicameral c. SYN: unilocular c.. unicameral bone c. SYN: solitary bone 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.. urinary c. SYN: urinoma. utricular c. dilation of the utricular lumen; usually unilocular. 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.

See cysto-.

cystacanth (sis′ta-kanth)
The fully developed larva of Acanthocephala, infective to the final host and with an inverted fully formed proboscis characteristic of the adult worm. [cyst- + G. akantha, thorn or spine]


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