The Roentgenologic Features of Mediastinal Tumors

Abstract

Although mediastinal tumors are not common, their incidence is frequent enough to warrant further investigation. Up to the present time their preoperative classification has proved difficult or impossible, but in view of the continued progress in the field of thoracic surgery, their differentiation prior to operation has become increasingly important. The present study was undertaken in an effort to determine whether any of these tumors had characteristic roentgenologic features. During the period from 1938 through 1942, 44 cases of proved mediastinal tumor were found among approximately 60,000 chests examined at the Massachusetts General Hospital. Malignant lymphoma and metastatic involvement of the mediastinal lymph nodes were not included in this study. Heuer and Andrus (3), in a monograph covering the literature up to 1940 and including their own cases, reviewed a great variety of mediastinal tumors and discussed their diagnosis and treatment. Our group is smaller and does not include as many different types of tumor, but all of the 44 cases were proved by operation, aspiration, or autopsy. The series included 25 congenital tumors—15 “bronchiogenic” cysts (6), 7 dermoid cysts, and 3 malignant teratomata—14 tumors of neurogenic origin, 1 malignant tumor, unclassified, and 4 tumors of the thyroid, parathyroid, or thymus glands. The last 4 included 2 intrathoracic goiters, one thymic tumor, and one tumor of the parathyroids. Congenital Tumors Bronchiogenic Cysts (6): From the roentgenologic point of view the most important diagnostic feature of a bronchiogenic cyst is a smooth, round or ovoid shadow arising anywhere within the mediastinum without evidence of bone erosion or calcification. Demonstration of tracheal attachment offers additional diagnostic evidence, but is not conclusive, since a substernal thyroid, an aneurysm of the innominate artery, and other masses may be attached to the trachea and may present a similar appearance. It should be remembered also that bronchiogenic cysts may grow within the lung as well as in the mediastinum. Unless the cyst becomes infected, its discovery is usually incidental. Those cysts in our series which became infected simulated lung abscess, or empyema with a bronchial fistula, in symptomatology and somewhat in their roentgen appearance. In the group of 15 the sex distribution was about equal, 8 males and 7 females. Dermoid Cysts (Fig. 1): All of the 7 dermoid cysts were in the anterior mediastinum. Only one was found in the upper portion; the others were located in the middle and inferior portions. As a rule, the outline of the dermoid cyst was slightly irregular as compared to the smooth, rounded outline of the bronchiogenic cyst. In size the dermoid cysts varied from 7 cm. to 17 cm. in diameter. Three showed calcification in the wall, one with actual bone formation. In one case, the cyst communicated with a bronchus and showed a fluid level, as well as what was apparently semisolid material.