Malignant pleural effusion from prostate adenocarcinoma

Prostate adenocarcinoma is the most common newly diagnosed cancer in males. Pulmonary and pleural metastasis are not uncommon on autopsy, but malignant effusions are not common clinical findings. There are no current recommendations to guide prostate specific antigen level assessment in pleural fluid. A 73 yo w/prostate cancer presented with complaints of subacute worsening of exertional dyspnea. He underwent a CT of the chest which excluded pulmonary emboli but did show moderate to large bilateral pleural effusions. The patient had a thoracentesis performed which confirmed an exudative effusion with atypical cells and elevated PSA levels. Metastatic visceral & parietal foci of prostate adenocarcinoma were found on medical pleuroscopy. The patient was symptomatically treated with bilateral tunneled chest tube catheters for intermittent drainage. Pulmonary metastasis secondary to prostate cancer is commonly found on autopsy, with pulmonary metastasis in 46% of patients and pleural metastasis in 21% of patients. Pleural effusions are not common, in one series, only 6/620 (1%) were found to have pleural masses/nodules or effusions. Diagnosis of pleural effusion secondary to metastatic prostate cancer can be achieved by direct cytology evaluation and/or PSA level elevation in the fluid. While specific, the sensitivity is not high enough to rule out disease if negative. Elevated pleural fluid PSA levels may aid in the diagnosis; however, there are no current recommendations as to what level may be considered diagnostic. Further studies are needed to define the sensitivity and specificity of PSA in pleural fluid.