A Cause of Bilateral Chylothorax: A Case of Mesothelioma without Pleural Involvement during Initial Diagnosis

Chylothorax is characterized by fluid accumulation in the pleural cavity containing chylomicrons due to disruption of lymphatic drainage in the thoracic ductus and development of chylothorax. A 60-year-old male patient presented to our clinic with shortness of breath and displayed bilateral pleural effusion and diffuse mediastinal lymph nodes in his computed chest tomography images. There were no thickening and nodular formation on the pleural surfaces. PET-CT showed no pathological FDG uptake. Thoracentesis showed a chylous effusion. Drainage reduced during monitoring could not be stopped; therefore, surgical intervention was considered. The patient underwent right thoracotomy. There were no pathological findings in the parietal and visceral pleura during the surgery. Initially lymphoma was considered. Perioperative samples were collected from the mediastinal lymph node. The pathology analysis reported metastasis of malignant mesothelioma. Evaluation of a repeated chest computed tomography showed nodular formations on the pleural surfaces. Mediastinal lymph nodes compressed the ductus thoracicus, resulting with chylothorax. The present case, with malignant mesothelioma, bilateral chylothorax, and mediastinal lymph node without any pleural involvement during initial diagnosis, is rare and will hence contribute to the literature.