Briasoulis E, Pavlidis N: Cancer of Unknown Primary Origin.

NCI: Cancer of Unknown Primary Origin (public domain)

Cancer of unknown primary origin (CUP) is the diagnosis when metastatic cancer is found but the place where the cancer began (the primary site) cannot be determined.

This includes cancer of the larynx, pharynx, oral cavity (oropharynx) and nasopharynx; additionally cancer of salivary glands and cancer of unknown primary origin (CUP).

In these cases, doctors refer to the primary tumor as "unknown" or "occult," and the patient is said to have cancer of unknown primary origin (CUP) or unknown primary tumors (UPT).

Carcinoma of Unknown Primary Home Page Cancer of Unknown Primary Origin Metastatic Cancer: Questions and Answers For general cancer information and other resources from the National Cancer Institute, see the following: