The patient was an 83-year-old male who had been working as a coal miner and was diagnosed with silicosis at another hospital at the age of 63. He had experienced repeated pericardial effusions 5 years ago and had undergone pericardiocentesis twice; however, the cause of pericardial effusion remained unclear, and he was referred to our hospital for surgical pericardial biopsy and pericardial fenestration.
He presented with general fatigue and exhibited stable vital signs. Fine crackles were heard during inspiration, and a restrictive pattern was observed on pulmonary function testing (vital capacity 2040 mL (71% predicted) and forced expiratory volume in 1 s 1550 mL (81.2% predicted)). We noted peripheral vein swelling and mild limb edema. Laboratory testing showed a white blood cell count of 4900/muL, hemoglobin levels of 11.3 g/dL, platelet count of 18.2 x 103/muL, and C-reactive protein levels of 0.06 mg/dL. No obvious liver or renal insufficiency (aminotransferase levels of 17 U/I, alanine transaminase levels of 6 U/I, total bilirubin levels of 0.2 mg/dL, total protein levels of 6.6 g/dL, albumin levels of 3.9 g/dL, blood urea nitrogen levels of 30.3 mg/dL, and creatinine levels of 0.8 mg/dL) was detected. His brain natriuretic peptide levels were 104.0 pg/mL. Low QRS voltage was observed on electrocardiography. A chest radiograph revealed cardiomegaly; his cardiothoracic ratio was 61.0% (Figure 1(a)). Opaque nodules measuring ~30 mm were observed bilaterally in the upper lung, and diffuse, small nodules were observed throughout the lung field and hilar region (Figure 1(a)). Transthoracic echocardiography and chest computed tomography both revealed massive pericardial effusion (Figures 1(b) and 1(c)). Additional findings on echocardiography included not only a right atrium collapse but also a hyperechoic pericardium and pericardial thickening (Figure 1(b)). In addition, there were no significant valvular disease and signs of heart failure (ejection fraction value of 84.0%, left ventricular end diastolic/systolic diameter of 39/18 mm, inferior vena cava diameter during inspiration of 18 mm, right ventricular systolic pressure of 29 mmHg, and E/e' value of 15.1). The patient was referred for a surgical pericardial biopsy to elucidate the cause of his repeated pericardial effusion and to perform pericardial fenestration.
Thoracoscopic surgery was performed using a 3 cm incision through the 8th intercostal space. Thoracoscopic examination again revealed serous pleural effusion and multiple nodular opacities throughout the pleura and pericardium (Figures 2(a) and 2(b)). A small incision was made on the pericardium (Figure 2(b)), taking care to preserve the left phrenic nerve, through which approximately 1200 mL of the effusion fluid was drained. We resected the pericardium largely of a 4 x 6 cm section using the Harmonic Scalpel  (Ethicon, US) and placed a drain in the left thoracic cavity.
Cytological examination of the pericardial biopsy sample was unremarkable; however, histopathological examination revealed inflammatory cell (mainly lymphocytes) infiltration and hyalinized fibrosis within the nodular tissue (Figures 3(a) and 3(b)), consistent with a diagnosis of silicosis. Lastly, polymerase chain reaction (PCR) results were negative for tuberculosis.
The patient's fatigue was resolved after surgery, and he experienced no recurrence of pericardial effusion at the 7-month follow-up.