View Abstract

A3997 - An Unusual Spirometry Flow-Volume Curve in a Patient with Severe Airway Obstruction Caused by a Tracheal Mass
Author Block: I. Amaza, R. Sanchez; Department of Medicine, University of Iowa Hospitals and Clinics, Iowa City, IA, United States.
INTRODUCTION
The flow-volume curve on spirometry in patients with variable intrathoracic airway obstruction is usually illustrated with a plateau in the forced expiratory flow. We present a patient with a history of tobacco use with clinical, radiographic and spirometry findings consistent with a diagnosis of, but not entirely explained by, severe chronic obstructive pulmonary disease (COPD).
CASE REPORT
A 58-year-old female presented to the clinic with 6 months of a refractory dry cough. Pertinent history included a 40 pack-year tobacco use and choroidal melanoma of the left eye diagnosed 8 years earlier. Tumor was treated with brachytherapy with complete resolution on further surveillance. A chest x-ray showed hyperinflated lungs and flattened diaphragm supporting the presence of emphysema. Spirometry demonstrated a forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) ratio of 39, FEV1 of 1.01 liters (39% predicted), FVC of 2.58 liters (81% predicted), consistent with severe airflow obstruction. The flow-volume curve on spirometry showed a relatively normal peak expiratory flow shape followed by a smooth flattening of the expiratory limb, a pattern more consistent with distal airway obstruction due to asthma or COPD. The patient was diagnosed with severe COPD and treated with long-acting bronchodilators but with no symptom improvement. A computed tomography scan of the chest performed two months later revealed a 1.5 x 1.5 centimeter intraluminal distal tracheal mass and diffuse emphysematous changes. Bronchoscopy was performed and revealed two tracheal lesions, a small lesion in the proximal trachea and a much larger lesion in the distal trachea nearly occluding the lumen. Both tracheal masses were completely resected endoscopically. Pathologic examination of the tracheal masses was consistent with metastatic melanoma. Following resection of the tracheal masses, the patient’s cough resolved, and follow-up spirometry showed a FEV1/FVC ratio of 65, FEV1 of 1.78 liters (70% predicted), FVC of 2.73 liters (83% predicted), and a near-normalized flow-volume curve.
DISCUSSION
Tracheal tumors are comprised of primary (such as squamous cell and adenoid cystic carcinomas) and metastatic neoplasms (such as melanomas and colon cancer). These usually manifest with persistent cough, hemoptysis, progressive dyspnea, stridor, and ultimately airway obstruction with respiratory failure. A delay in the diagnosis and treatment of these tumors can negatively impact overall prognosis and survival. As this case shows, severe variable intrathoracic airway obstruction does not always present with the typical flat expiratory loop on spirometry and a higher level of suspicion might be required for diagnosis.