Key Points

The commonly used term bronchial adenomas refers to a group of tumors arising beneath the bronchial epithelium or in bronchial glands. Unfortunately, adenoma suggests a benign process, which is accurate only in a relative sense. These tumors represent a spectrum of biologic activity that is quite broad. However, their clinical course is generally more benign than that of bronchogenic carcinomas. The more descriptive term for these tumors is bronchial gland tumors. Four distinct entities make up the majority of bronchial gland tumors: bronchial carcinoids, adenoid cystic carcinomas (cylindromas), mucoepidermoid carcinomas, and mucous gland adenomas. The four types of bronchial gland tumors are similar in that they arise from or occur in the trachea or bronchi and are typically less aggressive than bronchogenic carcinomas; however, the similarities end there. Together, these lesions account for 2% to 6% of all lung tumors.[1],[2] Adenoid cystic carcinoma (ACC), typical and atypical carcinoids, mucoepidermoid carcinoma, and mucous gland adenoma can be distinguished from one another on the basis of histology, immunostaining, histochemistry, genetics, and clinical activity. Each of these tumors is discussed in detail in this chapter.