A Case of Giant, Benign Schwannoma Associated with Total Lung Collapse by Bloody Effusion
A 36-year-old female presented with dyspnea with onset one week prior. Chest X-ray showed total opacity in the right lung (). Chest computed tomography revealed massive pleural fluid collection with total passive atelectasis of right lung. In addition, an inhomogeneous mass was found at the posterior portion of fluid collection (). The mass was well-circumscribed and showed minimal enhancement by radio-contrast dye (). A closed thoracentesis was performed and the aspirated pleural fluid was grossly bloody. Pleural fluid analysis was as follows: total protein 5.0 g/dL, lactate dehydrogenase 97 IU/L, glucose 96 mg/dL, pH 7.22, red blood cell 95,000/mm3, white blood cell 18/mm3 (differential count was impossible due to the small number of leukocytes), adenosine deaminase 21.9 IU/L. Cytologic exam was negative for malignant cell and a culture of pleural fluid did not grow any significant respiratory pathogens. Video-assisted thoracic surgery (VATS) revealed that right pleural cavity was filled with bloody fluid and a dumbbell-shaped tumor was found in the posterior thorax wall (). Because the mass was tightly fixated to the thoracic wall, VATS was converted into an open thoracotomy for the complete resection of the tumor. Upon removal, the mass was revealed to be a whitish soft tumor measuring 10.0×12.0×3.0 cm with a yellow cut-surface (). Upon microscopic exam, the tumor was composed of spindle cells with elongated nuclei, forming interlacing bundle with focal nuclear palisading. Mitotic figures were rare (). Immunohistochemical studies showed a strongly positive reaction with S-100 protein (data not shown). All of these findings are consistent with benign schwannoma. In the afternoon of the operation day, the patient complained of dyspnea and chest X-ray showed total haziness in the right lung (), which must have developed by re-expansion pulmonary edema after removal of massive pleural effusion. The patient was closely monitored in the intensive care unit with restriction of fluid administration. Several days later, the pulmonary edema was resolved and the patient was discharged on the 10th day after operation. Chest X-ray taken a month after the surgery showed full expansion of right lung ().