Carcinoma of Unknown Primary
When cancer is found in one or more metastatic sites but the primary site is not known, it is called a cancer of unknown primary (CUP) or an occult primary cancer.
All About Cancer of Unknown Primary
CUP is a metastatic cancer that has been diagnosed by a biopsy but the primary location, or the place where the cancer started, cannot be identified.
NCI articles related to cancer of unknown primary.
News stories related to cancer of unknown primary.