| arachnoid cyst | A fluid-filled cyst lined with arachnoid membrane, frequently situated near the lateral aspect of the fissure of Sylvius; usually congenital in origin. Synonym: leptomeningeal cyst. (05 Mar 2000) |
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| baker cyst | <radiology> Bursal fluid collection between: medial head of gastrocnemius muscle and, semimembranosus tendon, associated with knee injury, may contain osteocartilaginous fragments (12 Dec 1998) |
| Baker's cyst | <rheumatology> A synovial cyst or pouch that occurs in the synovial lining of the knee. Presents in the popliteal fossa (are behind the knee). Synovial fluid escapes from the knee joint and into the cyst in individuals who suffer from degenerative and other joint disease. Typically these cysts are not painful unless swelling is extensive. Aspiration of the cyst is therapeutic only temporarily since recurrence is common. most disappear spontaneously after several years. Larger cysts can be removed surgically. Rupture of a Baker's cyst can present with painless and swelling to the calf. (27 Sep 1997) |
| Bartholin's cyst | A cyst arising from the major vestibular gland or its ducts. (05 Mar 2000) |
| benign ear cyst | A disorder where there are noncancerous lumps or growths within the ear canal or on the pinna of the ear (external ear). most lumps are sebaceous cysts but some are bony overgrowths known as exostoses (or osteomas). If large enough they may interfere with hearing. In this case surgical removal may be required. (27 Sep 1997) |
| bile cyst | <anatomy> A digestive organ which stores bile (produced in the liver), used in the digestion and absorption of fats in the duodenum. (27 Sep 1997) |
| blood cyst | A cyst containing blood or resulting from the encapsulation of a haematoma. Synonym: blood cyst, haematocele, haematocyst, sanguineous cyst. (05 Mar 2000) |
| blue dome cyst | Cyst in the breast filled with serum and/or blood. With time they look blue. (16 Dec 1997) |
| botryoid odontogenic cyst | A type of lateral periodontal cyst that shows a multilocular growth pattern. (05 Mar 2000) |
| Boyer's cyst | A subhyoid cyst. (05 Mar 2000) |
| brachial cleft cyst | A cervical cyst arising from the persistence of ectodermal brachial cleft (groove) or endodermal pharyngeal pouches. (27 Sep 1997) |
| branchial cleft cyst | Also called a branchial cyst, this is a cavity that is a remnant from embryologic development present at birth in one side of the neck just in front of the large angulated muscle on either side (the sternocleidomastoid muscle). The cyst may not be recognised until adolescence as it enlarges its oval shape. Sometimes it develops a sinus or drainage pathway to the surface of the skin from which mucus can be expressed. Total surgical excision is the treatment of choice. Recurrence is not expected. (12 Dec 1998) |
| branchial cyst | Also called a branchial cleft cyst, this is a cavity that is a remnant from embryologic development present at birth in one side of the neck just in front of the large angulated muscle on either side (the sternocleidomastoid muscle). The cyst may not be recognised until adolescence as it enlarges its oval shape. It may develop a sinus or drainage pathway to the surface of the skin from which mucus can be expressed. Total surgical excision is the treatment of choice. Recurrence is not expected. (12 Dec 1998) |
| bronchogenic cyst | <radiology> Abnormality of primitive foregut (ventral segment = tracheobronchial tree; dorsal segment = oesophagus), lined with columnar respiratory epithelium, CT: water density (50%); higher density (50%); may have air/fluid level, mediastinal brochogenic cyst (86%), associated with spinal abnormalities, M:F = 1:1, stridor, dysphagia; usually assymptomatic, may communicate with tracheal lumen, location: posterior mediastinum (50%), pericarinal (35%), superior mediastinum (14%); usually on right, intrapulmonary bronchogenic cyst (14%), M>F; LL:UL = 2:1 (usually medial third), infection (75%), dyspnea, haemoptysis, 36% will eventually contain air (12 Dec 1998) |
| bursal cyst | A retention cyst in a bursa. (05 Mar 2000) |