pseudocyst

1. An accumulation of fluid in a cystlike loculus, but without an epithelial or other membranous lining. SYN: adventitious cyst, false cyst. 2. A cyst whose wall is formed by a host cell and not by a parasite. 3. A mass of 50 or more Toxoplasma bradyzoites, found within a host cell, frequently in the brain; formerly called a p., but now considered a true cyst enclosed in its own membrane within the host cell that may rupture to release particles that form new cysts, and apparently is infective to another vertebrate host. SEE ALSO: bradyzoite. [pseudo- + G. kystis, bladder]

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pseu·do·cyst 'süd-ō-.sist n

1) a cluster of toxoplasmas in an enucleate host cell

2) CYSTOID

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n.

a fluid-filled space without a proper wall or lining, within an organ. A pancreatic pseudocyst may develop in cases of chronic pancreatitis or as a complication of acute pancreatitis. As the pseudocyst, which is filled with enzyme-rich pancreatic juice, slowly expands it may cause episodes of abdominal pain accompanied by a rise in the level of enzymes in the blood. It may be felt by abdominal examination or seen by radiology or ultrasound examination. Treatment is by surgical drainage, usually by the technique of joining the pseudocyst to the stomach (marsupialization).

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pseu·do·cyst (sooґdo-sist″) [pseudo- + cyst] 1. an abnormal or dilated cavity resembling a true cyst but not lined with epithelium. Called also adventitious or false cyst. 2. a cluster of bradyzoites, small, comma-shaped forms of Toxoplasma gondii, enclosed by an irregular wall and sometimes containing thousands of organisms. It represents a resting stage, as opposed to the active, motile stage called the tachyzoite. Pseudocysts are found in the tissues, especially muscles and the brain, in chronic (latent) toxoplasmosis. Called also tissue cyst.