Enclosed in a capsule like a cyst.
Surrounded by a capsule or membrane.
Enclosed within a bladder-like wall. The term is applied to parasites, collections of pus, etc., which are shut off from surrounding tissues by a membrane or by adhesions.
Flukes, in their developmental journey, undergo a phase where they reside within a protective cyst or capsule. This particular stage of their life cycle finds them existing as larvae securely ensconced within cysts.