In Situ - Medicine

Medicine

In oncology: for a carcinoma, in situ means that malignant cells are present as a tumor but has not metastasized, or invaded, beyond the original site where the tumor was discovered. This can happen anywhere in the body, such as the skin, breast tissue, or lung. This type of tumor can often, depending on where it is located, be removed by surgery.

In anatomy: in situ refers to viewing structures as they appear in normal healthy bodies. For example, one can open up a cadaver's abdominal cavity and view the liver in situ or one can look at an isolated liver that has been removed from the cadaver's body.

In medicine, in situ means that cancer cells have not passed through the basal lamina. Basically, it means the tumor has not invaded the lamina propria or the deeper portions of the tissue. Because metastasis generally requires a carcinoma to 'break through' the basement membrane, chances of metastasis are very low.

In nursing, "in situ" describes any devices or appliances on the patient's body that remain in their desired and optimal condition. The term is most often used in documenting intact dressings or well-positioned intravenous devices.