cyst

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cyst,

abnormal sac in the body, filled with a fluid or semisolid and enclosed in a membrane. Cysts can be congenital but are usually acquired, the most common locations being the skin and the ovaries. Sebaceous cysts of the skin, known as blackheads or whiteheads, occur when dirt or other material blocks the oil glands of the skin, preventing secretions from escaping. Retention cysts develop in glandular organs when ducts are blocked, commonly in kidney tubules, mammary glands, and sweat glands. Most cysts can be aspirated for treatment and/or cytology (diagnostic purposes); often cysts require surgical removal.

Cyst

 

a cavity appearing in tissues and body organs as a result of various pathological processes.

True cysts are lined with epithelium or endothelium; false cysts have no special lining. Cysts are classified according to the mechanism of their development. Retention cysts form upon the disruption of the efflux of any glandular secretion which leads to dilatation of the gland or duct (for example, with clogging of the ducts of sebaceous, salivary, or mammary glands). Ramollissement cysts arise in compact tissue when the tissue softens (with hemorrhage, inflammation, necrosis) in a limited section (for example, a brain cyst, after infarction or hemorrhage). Dysontogenetic cysts form from a cystlike transformation of embryonic canals and fissures (for example, branchiogenetic cysts, from the vestiges of the gill slits) or from a defect in the development of an organ (for example, cystic kidneys). Tumorous cysts arise most often in glandular, vascular, or bone tumors for a variety of reasons (cystadenoma, lymphangioma). Traumatic cysts form with traumatic displacement of the epithelium and its embedding in the underlying tissues (epithelial cysts of the fingers, palms, iris). Parasitic cysts represent the vesicular stages (cysticerci) of tapeworms (Echinococcus, Cysticercus). The dimensions, structure, and external manifestations of cysts depend on their origin. Treatment is principally surgical.

V. V. SEROV

Table 1. The Cyrillic alphabet
Cyrillic Cyrillic 
Letters and namesNumerical valueGreek uncialLetters and namesNumerical valueGreek uncial
1Letters whose shape has changed 2Letters later dropped from the Russian alphabe:
Note: The names of some letters have meanings as words; they are shown in parentheses
ձ az (I)1ձϰ kher600ϰ
б buki  ѡ omega2800ѡ
ß vedi (know [imper.])2ßц tsy900 
ɾ glagol’ (word; verb)3ɾy cherv’ (worm)90 
A dobro (good)4ΔШ sha   
Є es!’ (is)5ЄШ shcha  
Table 1. The Cyrillic alphabetzhivete ([you] live)  ъ er  
S zelo2 (very)6ЅъI ery  
Z zemiia’ (earth)7Zь er’  
Ι i2 (and)10Ιъ iat’2  
H izhe’ (which; who)8H   
ĸ kako (how)20ĸ10 Iu  
Λ liudi (people)30λTable 1. The Cyrillic alphabet (i)ia1  
M myslete ([you] think)40mTable 1. The Cyrillic alphabet (i)e1  
N nash1 (our)50NA ius malyi2  
O on (he)70Oѫ ius bol’shoi2  
П pokoi (rest)80ПЉ iotized ius malyi2  
p rtsy100Pѭ iotized ius bol’shoi2  
C slovo (word)200CҘ ksi = (xi)260Table 1. The Cyrillic alphabet
T tverdo (hard)300TΨ psi2700Table 1. The Cyrillic alphabet
Oyuk1400 θ tita29Table 1. The Cyrillic alphabet
ϕ500Φγ izhitsa2 Table 1. The Cyrillic alphabet

Cyst

 

in the life cycle of many unicellular organisms, a stage characterized by the presence of a protective sheath, also called a cyst.

In animals (some flagellates, rhizopods, sporozoans, infusorians). resting cysts and reproductive cysts are distinguished. The thick jelly-like or solid walls of resting cysts consist of chitinous substances that sometimes become mineralized. The cysts form under unfavorable conditions, for example, when a body of water dries up or freezes over. In parasites, resting cysts ensure the transfer of one host to another through the external environment. Some protozoans can exist in cyst form for many months or years (for example, the genus Colpoda about 16 months, the genus Oicomonas about 5½ years, and the species Peridinium cinctum about 16½ years). Reproductive cysts have a thin wall and exist only for the short time during which their contents divide into several independent organisms.

In plants (peridinians, chrysomonads, Euglena), cysts result from compression of the body and extrusion onto the surface of a solid and virtually impermeable wall. Encystment usually occurs when environmental conditions deteriorate; it helps the organism to withstand the unfavorable period. When conditions turn favorable, the cysts germinate and their contents escape from the wall. A cyst usually produces a single new individual, but its contents sometimes divide, with several new individuals emerging from the cyst. In other words, reproduction occurs.

cyst

[sist]
(medicine)
A normal or pathologic sac with a distinct wall, containing fluid or other material.

cyst

1. Pathol any abnormal membranous sac or blisterlike pouch containing fluid or semisolid material
2. Anatomy any normal sac or vesicle in the body
3. a thick-walled protective membrane enclosing a cell, larva, or organism
References in periodicals archive ?
Different strategies have been described in treating patients with colloid cysts.
He reported his findings from the bioresonance follow-up testing of our son: residues of trauma and infection were not a problem, toxic metals and X-ray radiation (from brain X-rays and CT scans) were the issues, and explained that treating these conditions would minimize the chances for the colloid cyst to grow too, and for which he sent the next FCT-treatment.
Imaging of the head showed extensive chronic hydrocephalus and a 2 cm large colloid cyst of the third ventricle with obstruction of both foramina Monroe (Figure 3).
Colloid cysts within the brain can have serious consequences.
Optimal treatment of a colloid cyst of the third ventricle remains somewhat controversial.
For example, Aronica and colleagues recently described the case of an adolescent boy being treated with sumatriptan succinate for migraines, who died suddenly due to a colloid cyst of the third ventricle.
1 A report described a case of a colloid cyst of the velum interpositum in a young woman.
Besides colloid cysts, this device has a lot of applications for primary brain tumors and metastatic tumors," Dr.
In our case, the colloid cyst was well defined, spherical in shape with central hyperintensity and peripheral hypointense signal on T1 and central hypointensity and peripheral hyperintense signal on T2W1.
There were 4 cases of colloid cyst while one case of thyroglossal cyst.
George's wife was left immobile and with memory loss after she had a stroke during an op to remove colloid cysts, a type of brain tumour, three years ago.