A cyst that is too small to be felt but may be observed on mammography or ultrasound screening. ... (09 Oct 1997) ... 
(mi´kro-sist) a cyst visible only under a microscope.
A myxospore of a myxobacterium enclosed in a hard slime capsule.
Type: Term Pronunciation: mī′krō-sist Definitions: 1. A tiny cyst, frequently of such dimensions that a magnifying lens or microscope is required for observation.