- 1. SYN: h. cyst. 2. A vesicular structure resembling an Echinococcus cyst. [G. hydatis, a drop of water, a hyatid]- nonpedunculated h. SYN: appendix of testis.- pedunculated h. SYN: appendix of epididymidis.
* * *hy·da·tid 'hīd-ə-təd, -.tid n1) the larval cyst of a tapeworm of the genus Echinococcus that usu. occurs as a fluid-filled sac containing daughter cysts in which scolices develop but that occas. forms a proliferating spongy mass which actively metastasizes in the host's tissues called also hydatid cyst see ECHINOCOCCUS (1)b) HYDATID DISEASE
* * *n.a bladder-like cyst formed in various human tissues following the growth of the larval stage of an Echinococcus tapeworm. E. granulosus produces a single large fluid-filled cyst, called unilocular hydatid, which gives rise internally to smaller daughter cysts. The entire hydatid is bound by a fibrous capsule. E. multilocularis forms aggregates of many smaller cysts with a jelly-like matrix, called an alveolar hydatid, and enlarges by budding off external daughter cysts. Alveolar hydatids are not delimited by fibrous capsules and produce malignant tumours, which invade and destroy human tissues. See also hydatid disease.
* * *hy·da·tid (hiґdə-tid) [Gr. hydatis, water] 1. hydatid cyst. 2. any cystlike structure; see under mole.
Medical dictionary. 2011.