A 43-year-old female with dyspnoea was transferred to our emergency department for further treatment. She had dyspnoea and cough about 6 months ago. No sputum or haemoptysis was observed. She worked as a farmer for about 10 years, and such symptoms had never happened. Occupational poison contact was denied. Her parents were healthy, with no similar family history or medical history. Empiric anti-infective therapy and antituberculosis therapy were given in the last few months at a local hospital, but the symptoms of dyspnoea worsened. Plain CT of the chest revealed a mass with well-circumscribed soft-tissue attenuation, which measured about 25 Hounsfield units (HU) on the lateral wall of the trachea (Figure 1a,b). It was about 2 x 1 x 1 cm3 in size. Contrast-enhanced CT revealed marked homogeneous enhancement (Figure 2a-c), with the highest density of 122 HU in the arteries that declined gradually to 85 HU at 120 s after injecting the contrast medium. No metastatic lymph nodes or infiltration into nearby structures was observed. No similar lesions were found in the lungs, mediastinum or abdomen. Tracheotomy was arranged. Macroscopically, the mass was about 2 x 1 x 1 cm3 with a distinct border and smooth surface. No enriched vasculature was observed. Microscopically, the lesion was composed of a large amount of lymphatic tissue and hyperplastic vascular and lymphoid follicles, with atrophy of the germinal centre (Figure 3a,b). Immunohistochemical staining of the specimen confirmed the diagnosis of Castleman's disease (CD). The specimen was CD20(+)/CD79(+) in B lymphocytes and CD3(+)/CD5(+) in a few T lymphocytes. Plain CT of the chest 3 months after the surgery excluded relapse or residual lesions in the trachea. The patient was then under regular follow-up, and her physical condition was quite good.