Roentgenographic Aspects of Tracheal Tumors

Abstract

Tumors of the trachea are rare clinical entities. This relative immunity to tumor formation is difficult to understand, since the proximal and distal structures, i.e., larynx and bronchi, are so frequently the sites of neoplastic disease. Holinger et al. (14) reported that the frequency of tumors of the trachea, as compared to laryngeal tumors, ranged from 1∶300 to 1∶800. Clegg (6) found 5 tracheal carcinomas and 1,623 cases of bronchial cancer during the same five-year period. Because of the rarity of tracheal tumors, they are seldom considered in the differential diagnosis of respiratory disease and, for that reason, often remain undetected during life. Whitby (33) reported a case of a large carcinosarcoma of the trachea which was discovered only at autopsy. Bronchoscopy failed to reveal the tumor on the posterior wall of the subglottis and upper trachea, and the author suggested that x-ray studies might have been diagnostic. Andrén (1), in 1937, published a case of a posterior-wall tracheal tumor detected on a lateral roentgenogram of the neck. Prior to this report there had appeared in the literature only 3 cases in which the diagnosis was made before operation. It is, indeed, surprising how few of these tumors have been diagnosed antemortem. In many instances the abnormal roentgenographic appearance of the trachea was not appreciated except in retrospect. It is for this reason that we are presenting our experience with 5 examples of tracheal tumors and a discussion of the advantages and limitations of the various roentgeno-graphic technics for their demonstration. Pathology In a large series of tracheal tumors there was an almost equal distribution between benign and malignant (11). The benign tumors include adenoma, fibroma, papilloma (2, 4, 30), hemangioma (5), hamartoma (9), and leiomyoma (27). Most authors also include in the benign group such nonneoplastic masses as amyloid (7, 15), xanthoma, scleroma (12, 20), aberrant thyroid tissue (32), inflammatory granuloma (14), and tracheopathia osteoplastica (14, 16). This last is a rare but interesting entity characterized by osseous and cartilaginous growths occurring between the tracheal rings beneath a normal mucosa, usually limited to the lower two-thirds of the trachea. These multiple nodules cause a scalloped appearance to the inner tracheal wall, or the nodules may coalesce and cause diffuse narrowing of the tracheal air column (28). Primary malignant tumors of the trachea include squamous carcinoma, adenocarcinoma, and cylindromas (8, 25, 26, 33). Secondary invasion by carcinomas arising from adjacent organs, particularly the thyroid, esophagus, and lung, is also encountered. The cylindroma is a specific type of adenocarcinoma characterized by well differentiated cords of cells; it is found in the salivary glands or upper respiratory tract (31). In the past it has been referred to as adenoid cystic carcinoma, adenocystic basal-cell carcinoma, basaloma, and malignant adenoma.