Benign Fibrous Histiocytoma of the Lung With a Polypoid Growth in the Lumen of the Bronchus-a Report of Resected Case-

We experienced a relatively rare case of benign fibrous histiocytoma of the lung with a vulnarable polypoid growth in the lumen of the bronchus. A 20-year-old male was admitted to the hospital for evaluation of an abnormal shadow on the left pulmonary hilum, which was pointed out at a medical checkup. Chest CT scan showed a well enhanced tumor 3cm in diameter in the S3 segment close to the left upper trunk of the pulmonary artery without having abnormalities of the distal lung. The tumor was sharply demarcated and there was no calcification. Bronchoscopic examination revealed the red polypoid lesion which mostly occupied the lumen of the left upper division bronchus. The external surface of the polypoid lesion was smooth and glossy, but the orifice of the upper division of the bronchus showed hypervascularization. The tumor was very vulnarable and it was impossible to perform biopsy. For a risk of bleeding and making the definite diagnosis, left upper lobectomy was performed. Inspection of the operation showed minimal adhesions at the apex, but free fluid was not seen in the left pleural cavity. The tumor was sharply demarcated from the adjacent pulmonary parenchyma and protruded in a polypoid manner into the bronchial lumen with intact covering of bronchial mucosa. The overlying pleura was smooth. On cut section, the lesion was solid and yellow with focal bleeding. Histologically, no limiting fibrous capsule was noted. The tumor tissue was composed of fibroblast-like spindle cells and mixed histiocytes, showing occasional storiform pattern. Infiltration of plasma cells was also seen. Mitoses or atypical cells were minimal in the tumor. A typical fibrous histiocytoma was reported with prominent bronchial ectasia in its visinity.