Discussion
This radiograph demonstrates a well circumscribed mass in the left upper chest. There is no silhouetting of the posterior arch and proximal descending aorta, placing the mass outside of the posterior mediastinum. The finding is subtle, but the anterior left 1st rib should project over the mass but is not visualized. This finding localizes the mass to the anterior chest wall with 1st rib involvement. This patient has a diagnosis of multiple myeloma, which favors plasmacytoma as the diagnosis.
Also partly visualized is a left proximal humerus repair using fixation hardware and cement osteoplasty, necessitated by prior pathologic fracture in the setting of a myelomatous lesion. The exam is otherwise normal.