Definition of In situ

1. Atrial Fibrillation Slideshow Pictures
2. Bad Bugs and Their Bites Slideshow
3. Understanding Ulcerative Colitis Slideshow

In situ: In the normal location. An in situ tumor is one that is confined to its site of origin and has not invaded neighboring tissue or gone elsewhere in the body. For example, squamous cell carcinoma in situ is an early stage of skin cancer.