A tracheal lesion simulating an aneurysmal bone cyst.

A 37-year-old man presented to the emergency department with the chief complaints of persistent cough and shortness of breath for approximately 2 months. At least two episodes of mild hemoptysis prior to presentation were reported. His past medical history was signifi cant only for chronic low back pain secondary to multiple herniated discs. Th e chest radiograph at the time of presentation showed a subtle nodular opacity projecting over the region of the distal trachea (Figure 1). Th e lungs were clear. Subsequent chest computed tomography (CT) demonstrated a soft tissue mass measuring up to 1.7 cm in the distal trachea at the level of the aortic arch (Figure 2). A small central focus of calcifi cation was present in the lesion. Th e mass appeared to arise from the right anterolateral tracheal wall and invade the adjacent mediastinum. Th e diff erential diagnosis included primary malignancies of the trachea such as squamous cell carcinoma, adenoid cystic carcinoma, mucoepidermoid carcinoma, and carcinoid. Benign tracheal tumors such as papilloma, hamartoma, leiomyoma, and amyloidoma were also considered. Rigid bronchoscopy demonstrated that the mass was located 1.5 cm cephalad to the carina and occupied approximately 80% of the tracheal lumen. Following biopsy, pathology initially reported a mesenchymal spindle cell tumor with bone and numerous osteoclastlike giant cells. Th e tumor was subsequently resected and tracheal reconstruction was performed. Final pathology demonstrated the previous fi ndings, as well as blood-fi lled cystic spaces surrounding cartilaginous elements (Figure 3). Th ese fi ndings were consistent with an aneurysmal bone cyst arising from and extending through the cartilaginous rings of the trachea. No additional lesions were identifi ed within the tumor specimen or the resected tracheal segment.