INTRODUCTION: Endotracheal schwannomas remain an exceedingly rare cause of airway obstruction. The first reported case of neurogenic intrapulmonary tumor was in 1914. Patients are generally asymptomatic until the tumor reaches a critical size, at which point, obstructive symptoms are seen. Since 1950, only a few dozen of these cases have been reported. We present a case of a man who presented with shortness of breath and cough and was found to have an obstructing tracheal schwannoma.
CASE PRESENTATION: A 70-year-old man presented to the emergency department with complaints of productive cough and dyspnea. His past medical history was significant for Chronic Obstructive Pulmonary Disease (COPD), 20-pack-year smoking history, hypertension, and hyperlipidemia. He was admitted for presumed acute COPD exacerbation and physical exam was notable for mild respiratory distress. Despite treatment with bronchodilators, antibiotics, and intravenous glucocorticoids, he continued to experience shortness of breath. While supine, stridor was audible and radiated to both lungs. A Computed Tomography (CT) scan of the neck and thorax revealed a 2.2 x 1.4 cm endotracheal mass. No lung nodules or lymphadenopathy was seen. Pulmonary Function Test (PFT) demonstrated flattening of the flow volume loop. Flexible bronchocopic evaluation revealed a pedunculated endobronchial mass obstructing 90% of the tracheal lumen. Rigid bronchoscopy was subsequently performed with excision of the tracheal mass. Characteristic histologic elements, and diffuse staining of the protein S-100, established the diagnosis of schwannoma. The remainder of his hospitalization was uneventful. Post resection PFT revealed resolution of the central airway obstruction. Surveillance bronchoscopy at one year was negative for recurrence of the lesion.
DISCUSSIONS: Primary tracheal tumors are less prevalent than bronchial tumors. Two thirds of all primary tracheal tumors are evenly divided between squamous cell carcinoma and adenoid cystic carcinoma. The remaining types of primary tracheal tumors encompass a wide spectrum of lesions including malignant, intermediate, and benign tumors (1). Primary neurogenic tumors of the trachea (schwannoma) are extremely uncommon and symptoms of airway obstruction predominate (2). Generally, patients are symptomatic only when more than half of the cross sectional area of the trachea is obstructed (1). In light of this, incidental masses may be found in entirely asymptomatic patients. The most common presenting symptom associated with these tumors is dyspnea. Chest X-Ray is interpreted as normal in 30-75% of patients, thus, leading to the inappropriate treatment of presumed asthma and/or COPD (1). When tracheal tumor is suspected, the most important and preferred test for diagnosis is rigid bronchoscopy (1). Compared to flexible bronchoscopy, rigid bronchoscopy provides more secure control of the obstructed airway and control of potential bleeding that may occur after biopsy (1). When present, schwannomas are typically circumscribed and encapsulated tumors (2). Histologically, schwannomas have regions of high and low cellularity called Antoni A and Antoni B areas, respectively. The protein S-100 can also be stained to confirm the diagnosis. Strong expression of S-100 is associated with benign tumors, whereas minimal or only focal expression of this protein is suggestive of a malignant lesion (2).
CONCLUSION: Despite their low prevalence, tracheal tumors should be suspected when considering patients with persistent symptoms of dyspnea and obstruction. Follow up surveillance bronchosopies are recommended as the long-term natural progression and recurrence rates of tracheal schwannomas are unknown.
DISCLOSURE: Gabriel Gomez, No Financial Disclosure Information; No Product/Research Disclosure Information