“…For our patient, the left pleura was signi cantly thickened and calci ed so that the puncture needle had signi cant resistance to entry. Pleural thickening can indicate several diseases, such as malignant mesothelioma, tuberculous pleuritis, primary or secondary pleural lymphoma, metastatic lung cancer, ectopic thymoma, and sarcomatoid carcinoma (21) . The differential diagnosis included mesothelioma, adenocarcinoma, primary pleural sarcoma, thymic epithelial tumors, lymphoma, and other metastatic tumors (7) .…”