[Two cases of metastatic lung cancer examined by bronchoscopic cytology]

We herein report two cases of metastatic lung cancer examined with bronchoscopic cytology. The first case involved a 43-year-old female, who had undergone low anterior resection of the rectum for rectal cancer three years earlier. Routine chest X-ray showed a nodular lesion in the left upper area. Bronchoscopic examination revealed a mass occluding the left upper bronchus. Simultaneous bronchoscopic biopsy and washing cytology were performed. The cytological specimen consisted of cell clusters with tall columnar epithelium arranged in a palisading manner. The cytological findings strongly suggested metastatic adenocarcinoma originating from the colorectal region. The patient died from respiratory failure. Autopsy confirmed metastatic deposit of adenocarcinoma in the lung. Histologically, the tumor invaded the overlying bronchial wall and was exposed in the lumen. The second case was an 80-year-old female, who had been diagnosed as gastric cancer by the endoscopic examination one year earlier. She had refused surgical treatment. Routine chest X-ray showed reticulonodular lesions disseminated throughout the bilateral lungs. Bronchial endoscopy presented edematous mucosa of the right lower bronchus. Brushing cytology as well as punch biopsy were taken. Cytological examination revealed atypical cells with increased N/C ratio and reduced cohesiveness. The lesion was diagnosed as metastatic adenocarcinoma of gastric origin from cytological findings and clinical history. The patient died from respiratory failure. Postmortem examination revealed cancer cells in the lymphatic channels of the bronchial wall. Our two cases indicate that bronchoscopic cytology is useful for estimating the origin of metastatic cancer.