Axillary tumors as a cause of false mediastinal mass shadows on lateral chest films.

Abstract

A 72-year-old Negro female who had been known to have lymphosarcoma for a period of two years complained of malaise and cough. She was referred for radiographic examination of the chest, which was done by the postero-anterior and left lateral 6-foot technics which are routine at Parkland Hospital. An anterior mediastinal mass was readily appreciable in both projections (Fig. 1). Superimposed upon the upper posterior portion of the cardiac silhouette in the lateral film was an additional density, whose curvilinear anterior margin was clearly defined though the posterior margin could not be identified. A course of radiotherapy for a tumor dose of 2,500 rad was delivered through opposing ports to the superior mediastinum, with the result seen in Figure 2. The upper mediastinal tumor itself had resolved, but the curvilinear mass shadow, uneasily described as an artefact on the first study, was again apparent in the right lateral projection. Physical examination disclosed a soft, pliable right axillary mass identifiable as the residual following a course of radiotherapy delivered to the right axillary lymph nodes at another hospital two years before. On inspection of the axilla with the patient positioned as for a lateral chest film, it could be seen that the anterior margin of the mass was clearly defined and projected well above the surface of the surrounding axillary contents, to disappear posteriorly under the dorsal muscle groups, accounting for its radiographic appearance. The sharp anterior margin was not a result of compression against the cassette holder, for this margin was equally well delineated on both left and right lateral films. Having become aware of the possibility of false mediastinal mass shadows originating in axillary tumors, we discovered 5 additional examples during the following years and learned to distinguish the false mass shadow from a similar density which may be caused by heavy anterior axillary folds. Surprisingly, this radiographic finding seems not to have been described before, so far as we could determine on an extensive search of the literature. Additional work on the radiographic properties of the axilla is now under way, and the entire subject will be reported exhaustively at a later date.