Differential diagnosis between lymphoma-associated malignant pleural effusion and tuberculous pleural effusion

Chang Ho Kim, Hong Geun Oh, Sang Yub Lee, Jae Kwang Lim, Yong Hoon Lee, Hyewon Seo, Seung Soo Yoo, Shin Yup Lee, Seung Ick Cha, Jae Yong Park, Jaehee Lee


Background: Lymphoma-associated malignant pleural effusions (L-MPE) can mimic tuberculous pleural effusion (TPE) characterized by lymphocytic exudate with high adenosine deaminase (ADA) levels. Furthermore, the low cytological yield of L-MPE makes differentiation between L-MPE and TPE more challenging. However, there are few data regarding differential diagnosis of L-MPE and TPE.
Methods: All consecutive patients diagnosed with L-MPE or TPE between January 2011 and December 2016 were retrospectively recruited using the Electronic Medical Record database. Clinical symptoms and laboratory and pleural fluid data [including serum lactate dehydrogenase (LDH), C-reactive protein, and pleural fluid ADA levels] were compared between L-MPE and TPE. Useful variables in the differential diagnosis of L-MPE and TPE were evaluated by multivariate logistic regression analysis.
Results: Seventeen patients with L-MPE and 216 patients with TPE were included in this study. In the multivariate analysis, fever was negatively associated with L-MPE [odds ratio (OR): 0.175, 95% confidence interval (CI): 0.033–0.941, P=0.042], while serum LDH levels were positively associated with L-MPE (OR: 1.005, 95% CI: 1.003–1.007, P<0.001). Serum LDH >460 U/L provided a sensitivity of 76% and a specificity of 81% to distinguish L-MPE and TPE. In contrast, serum C-reactive protein and pleural fluid ADA levels were not significantly different between the groups.
Conclusions: Patients with L-MPE and TPE present very similar clinical, laboratory, and pleural fluid characteristics. Fever and serum LDH levels may be helpful in guiding the differential diagnosis of L-MPE and TPE. Lymphoma should be kept in mind in the differential diagnosis in patients with lymphocytic pleural effusion and high ADA levels.