Carcinoma at a pre-invasive stage in which malignant cells are confined to the epithelium, with no extension through the basement membrane or into adjacent structures; an instance of this.
Origin
1930s. From carcinoma + in situ.
Definition of carcinoma in situ in US English:
carcinoma in situ
noun
Medicine
Carcinoma at a pre-invasive stage in which malignant cells are confined to the epithelium, with no extension through the basement membrane or into adjacent structures; an instance of this.