A case in which cancer cells are found in the body, but the place where the cells first started growing (the origin or primary site) cannot be determined. Also called cancer of unknown primary origin and carcinoma of unknown primary.

Source: NCI Dictionary of Cancer Terms

In carcinoma of unknown primary, cancer cells have spread in the body but the place where the primary cancer began is unknown. En el carcinoma de sitio primario desconocido las células cancerosas se han diseminado en el cuerpo pero no se sabe dónde empezó el cáncer primario. 2006-12-21 Date last modified: 2015-03-30Carcinoma of Unknown PrimaryCarcinoma de tumor primario desconocido