Subtle radiographic presentation of a pleural effusion secondary to a cancer of unknown primary: a case study.

Carcinoma of unknown primary sites is a clinical syndrome that represents many types of cancer. The mortality rate associate to this type of cancer is elevated and a rapid medical referral is required for patients presenting this condition. Pleural effusion may be the only visible sign. We report a case of pleural effusion secondary to a cancer of unknown primary site in a 60-year-old man that sought chiropractic care for radiating low back pain. The radiographic studies revealed a pleural effusion as one of the only significant finding. This article will address the clinical presentation, radiographic studies and a discussion on the radiographic detection of pleural effusion.