Evaluation of airway resistance in primary small cell carcinoma of the trachea by MostGraph: a case study

The case subject was a 58-year-old woman who presented to our hospital with a chief complaint of respiratory discomfort. Wheezing could be heard in both lungs; treatment was initiated with inhaled steroids for suspected bronchial asthma. However, 1 week later, the respiratory discomfort had not improved and the wheezing sound had progressed to the neck area. Upper airway obstruction was suspected; therefore, chest computed tomography (CT) was performed, revealing tracheal stenosis caused by a tumor in the upper airway. Because of the high risk of airway obstruction, tracheotomy and tracheal tumor resection were performed. Histopathological examination of the resected tumor revealed small cell lung cancer (SCLC); the stage was determined to be clinical stage IIIB (cT4N2M0), for which chemotherapy with two cycles of cisplatin plus etoposide followed by radiation therapy were administered. Pulmonary function testing revealed no change in the forced expiratory volume in 1 sec and flow volume (FV) curve before and after tumor resection, whereas airway resistance measured by MostGraph-01 showed a marked decrease following treatment. We believe that MostGraph-01 may be useful for measuring airway resistance and evaluating a tracheal tumor, and report a case using MostGraph-01.