We report a case of adenocarcinoma detected in the right pleural effusion of a 75-year-old woman. Investigations failed to reveal the site of the primary lesion, and the case was treated as primary unknown cancer. The pleural effusion disappeared after chemotherapy; however, as there was serious bone marrow suppression, the clinical course was observed at an outpatient clinic without chemotherapy. A search for the primary lesion was repeated, but it was not found. One year after first admission, a chest X-ray showed left pleural effusion. Adenocarcinoma was detected in the effusion and a tumor mass obtained from the pleural cavity. Ovarian cancer was diagnosed based on the histological, serological and MRI findings. Thus, this was a rare case of ovarian cancer in which the diagnosis was confirmed by repeated evaluation and in which the initial diagnosis had been primary unknown cancer with malignant pleural effusion only.
Ovarian Cancer ; Pleural Effusion, Malignant ; Pleural Effusion ; Unknown ; Beginning