Incidental Finding of a Tracheal Lipoma

Abstract

Introduction: Primary tracheal tumors are rare with an incidence of 0.2/100,000 persons, accounting for 0.6% of all pulmonary tumors. Only 10-20% of these tumors are benign with the most common being recurrent respiratory papillomatosis. Other benign tracheobronchial tumors include hamartoma, fibroma, lipoma and hemangioma among others. Due to the slow growing nature of these tumors, patients may present with progressive exertional dyspnea, cough and recurrent pneumonia, though rarely these tumors are identified incidentally in asymptomatic patients. This case describes a patient with an who underwent successful resection with flexible bronchoscopy and snare electrocautery. Case Report: A 66-year-old male with a history of former tobacco use was admitted to the medical intensive care unit (ICU) in 11/2020 with COVID-19 pneumonia, and incidentally found to have a tracheal tumor noted on CT imaging. His ICU course was complicated by submassive pulmonary embolism, pneumothorax requiring chest tube, and acute hypoxemic respiratory failure requiring heated high-flow nasal cannula. He was successfully discharged to home after 4 weeks and evaluated in the ambulatory clinic for follow-up 2 months later. Review of his imaging from an outside facility demonstrated a 1-cm polypoid lesion arising from the right tracheal wall (Figure 1A). Pulmonary function testing demonstrated a moderate restrictive defect with normal flow-volume loops. He was referred to interventional pulmonology for further evaluation and management. Flexible bronchoscopy revealed a 50% partially obstructing polypoid mass 6-cm distal to the vocal cords (Figure 1B). The mass was excised using snare electrocautery with subsequent cryotherapy for destruction of abnormal tissue at the base of the lesion and argon plasma coagulation for hemostasis. Pathology revealed tracheal lipoma. Repeat flexible bronchoscopy 12 weeks later revealed no evidence of recurrence at the site of the previously resected tracheal lipoma (Figure 1C). Discussion: Among benign tracheobronchial tumors, lipoma is an extremely rare diagnosis representing only 3-9% of cases. Airway lipomas very rarely involve the trachea and are infrequently found incidentally in asymptomatic patients. Epidemiological risk factors are thought to include male gender, obesity, middle age, and smoking. Flexible tracheobronchoscopy remains the gold standard for diagnosis, also allowing for excisional treatment with electrocautery, cryotherapy, or laser therapy. Given the rare incidence of these tumors, follow-up evaluation is recommended, though to-date there are no reports of local recurrence after bronchoscopic treatment. This case highlights the importance for diagnostic evaluation of incidental tracheobronchial tumors given the rare incidence of benign diagnoses.