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.
A cyst formed around a foreign body.
Dilation and rupture of pulmonary alveoli to form air cysts.
A cyst near the apex of the root of a nonvital tooth.
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)
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 cystCervical cyst.
A cystic mass in bone, usually a normal variant or a benign tumor.
Boyer cyst See: Boyer cyst
A closed epithelial sac derived from a branchial groove of its corresponding pharyngeal pouch. Synonym: branchial cyst
An ovarian cyst with darkly pigmented gelatinous contents.
A cyst with gelatinous contents.
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.
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.
A cyst growing out of the walls of another cyst.
A cyst that forms from any of the odontogenic tissues.
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
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.
A cyst formed in a natural enclosed cavity, such as a follicular cyst of the ovary.
echinococcus cystHydatid cyst.
An ovarian cyst or tumor lined with endometrial tissue, usually seen in ovarian endometriosis.
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 cystDentigerous cyst.
A cyst arising from hemorrhage or escape of other body fluids into tissues.
A cyst caused by trapping of an exudate in a closed area.
FOLLICULAR CYST: Follicular cysts seen on ultrasonography of the thyroid gland.
A cyst arising from a follicle, as a follicular cyst of the thyroid gland, the ovary, or a forming tooth. Synonym: dentigerous cyst
ganglion cystganglion (2)
Gartner cyst See: Gartner cyst
Gorlin cyst See: Gorlin cyst
A cyst formed by the growth of the larval form of Echinococcus granulosus, usually in the liver. Synonym: echinococcus cyst
A cyst resulting from displacement of portions of the epidermis, as may occur in injuries.
A cystic formation between the layers of the broad ligament.
A cyst occurring in the normal involution of an organ or structure, as in the mammary gland.
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
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
A hydatid cyst enveloping smaller ones.
A retention cyst composed of mucus.
A cyst caused by closure of the ducts of the nabothian glands in the uterine cervix as a result of chronic cervicitis.
A cyst associated with the teeth, such as a dentigerous or radicular 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
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.
A cyst of the parovarium.
periapical cystRadicular 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
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 cystBaker cyst.
An anomalous cavity of the brain that communicates with the ventricular system.
A cyst lined with epithelium that proliferates, forming projections that extend into the cavity of the 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
A cyst retaining the secretion of a gland, as in a mucous or sebaceous cyst.
root-end cystRadicular cyst.
sebaceous cystEpidermoid cyst.
A cyst of the epididymis, ductus deferens, or other sperm-carrying ducts that contain semen.
A cyst of the hypophyseal stalk just above the floor of the sella turcica. Its wall is frequently calcified or ossified.
Accumulation of synovia in a bursa, synovial crypt, or sac of a synovial hernia, causing a tumor.
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 cystPilar cyst.
An ovarian cyst that ruptures into the lumen of an adherent uterine tube.
A cyst containing only one cavity.
A cyst in the vagina.
A congenital cyst of the gastrointestinal canal. Lined with ciliated epithelium, it is the remains of the omphalomesenteric duct.
A cyst lying in one of the broad ligaments of the uterus.illustration