Pleural Effusion in Multiple Myeloma: Characteristics and Practice Patterns.

In many Asian countries battling with the double burden of increasing noninfectious diseases on top of infectious diseases, multiple myeloma (MM) patients presenting with pleural effusion (PE) pose a great diagnostic challenge. Thus, we aimed to analyze the clinical features and practice patterns of such patients. This is a multicenter retrospective study of newly diagnosed MM patients between January 2011 and December 2015. Among 575 MM patients diagnosed during the study period, 80 (13.9%) that were associated with PE were identified and analyzed. The most common cause of PE was parapneumonic (25%), followed by reactive (18.8%). Higher CRP levels and leukocytosis were indicators of parapneumonic PE. There were 7 (8.8%) with myelomatous PE and 2 (2.5%) with tuberculosis. Fifty-six patients underwent additional examinations to determine the exact cause of effusion; 28 patients received computed tomography (CT) of the chest, 5 patients underwent thoracentesis/biopsy, and 23 patients underwent both CT and thoracentesis/biopsy. On the other hand, 24 patients did not undergo additional analyses but were treated empirically. Real-world analyses of practice patterns in MM patients with PE showed the suboptimal use of invasive procedures to determine the exact cause of PE. Since reversible causes and tuberculosis pleurisy are not uncommon, invasive procedures should be actively incorporated as needed.