Granulocyte-Macrophage Colony-Stimulating Factor and Granulocyte Colony-Stimulating Factor-Producing Malignant Pleural Mesothelioma Accompanied by Eosinophilic Pleural Fluid

Background. Malignant pleural mesothelioma (MPM) is relatively rare. This disease was diagnosed with difficulty by pleural fluid analysis and radiographic findings. The following is a report on a case of granulocytemacrophage colony-stimulating factor (GM-CSF) and granulocyte colony-stimulating factor (G-CSF)-producing MPM accompanied by eosinophilic pleural fluid. Case. A 65-year-old man was admitted with right chest and back pain on July 29, 2002. The eosinophil count in the pleural fluid and the findings of computed tomography (CT) suggested eosinophilic pleurisy. Despite steroid therapy, his symptoms rapidly worsened. The white blood cell (WBC) count elevated to 28260/mm3 and the G-CSF level of the serum elevated at 50 pg/dl. A pleural biopsy under video-assisted thoracoscopic surgery (VATS) was performed on September 17, 2002. Histopathologically, the tumor cells consisted of tubular and nest structures from atypical epithelial cells and spindle-shaped cells. The biphasic type of MPM was diagnosed by the pathological findings. The cytoplasms of almost all tumor cells were immunohistochemically stained with anti-GM-CSF monoclonal antibody. The cytoplasms of 5 percent of tumor cells were immunohistochemically stained with anti-G-CSF monoclonal antibody. He had complications with empyema due to prolonged air-leakage. After 17 weeks, he died on November 27, 2002. The autopsy revealed that the tumor had spread to the pleura and pericardium in the thoracic cavity, and penetrated the diaphragm to involve the peritoneum, the small intestine and colon. Conclusion. Even in patients with inflammatory reaction and pleural effusion resistant to treatment, MPM should be considered in the differential diagnosis of tissue biopsy under VATS.