Primary tracheal malignant lymphoma detected during a regular checkup in an asbestos dust-exposed smoker

Primary tracheal malignant lymphoma is a rare disease; only 30 cases have been reported to date. A 73-year-old Japanese man with a history of asbestos exposure was undergoing biannual chest computed tomography (CT) twice a year as a routine procedure for those previously exposed to asbestos. He had been smoking since the age of 32. In September 2010, chest CT during this regular checkup revealed a polypoid lesion in his trachea and pleural plaques, which were suspected to be caused by asbestos. Bronchoscopy performed in October revealed a polypoid lesion with granules and nodules in the trachea. A diagnosis of non-Hodgkin lymphoma (NHL) and extranodal marginal-zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) was confirmed by histological analysis of the biopsy specimens. To our knowledge, this is the first case of primary tracheal lymphoma associated with a history of asbestos exposure. Several reports have documented no correlation between asbestos and malignant lymphoma. In addition, the correlation between smoking and NHL is weak. Although we cannot exclude the possibility of a simple coincidence of asbestos, smoking, and tracheal lymphoma, this case suggests that asbestos and smoking might have multiplicative effects in the development or progression of tracheal lymphoma.