Invasion of tissue immediately adjacent to a carcinoma in situ, the earliest stage of malignant neoplastic invasion. ... (05 Mar 2000) ... 
(mi″kro-in-va´zhәn) microscopic extension of malignant cells into adjacent tissue in carcinoma in situ. adj., microinva´sive., adj.
Type: Term Pronunciation: mī′krō-in-vā′zhŭn Definitions: 1. Invasion of tissue immediately adjacent to a carcinoma in situ, the earliest stage of malignant neoplastic invasion.