Rationale: Extramedullary plasmacytomas (EMPs) are rare solitary soft tissue tumors characterized by monoclonal proliferation of plasma cells. Most lesions occur in the head and neck, but primary tracheal lesions are very rare. Patient Concerns: In this report, we describe a case of tracheal EMP discovered in a 48-year-old man who presented with a history of progressive dyspnea. Diagnoses: Computed tomography (CT) revealed a well-defined nodular mass in the posterior wall of trachea without signs of invasion of the tracheal walls. Then, a reddish mass occluding approximately 90% of the trachea was evidenced by bronchoscopic examination. Interventions: The patient was treated with surgery followed by adjuvant radiotherapy to achieve better local control. Outcomes: After the surgery, there was immediate symptomatic relief. There was no recurrence or metastasis during a 6-month follow-up. Lessons: This study presents a rare case of tracheal EMP occluding approximately 90% of the lumen that was successfully managed by surgery followed by radiotherapy.