Reason: assess for metastatic sarcoma History: left axillary and flank painAdditional history collected from electronic medical record: 28-year-old man with history of low-grade fibromyxoid sarcoma of the left shoulder, located about the left brachial plexus. He is status post radiation therapy and surgical excision, with positive surgical margins. The field of view was increased to include more of the axilla, although the postoperative and inflammatory changes described below extend medially off the field of view of this study.There are multiple foci of signal void within the anterior soft tissues, reflecting metallic susceptibility artifact from prior surgery. There is also metal susceptibility artifact along the clavicular diaphysis, representing a plate and screw device seen on prior CT scan. There is reticular band-like signal abnormality and enhancement within the deep fat anterior to the subscapularis, which we suspect reflects scar tissue and/or changes from radiation therapy, with similar enhancement noted along the deltopectoral groove. There is an amorphous collection of heterogeneous signal intensity anterior to the subscapularis muscle and adjacent to the lateral margin of the axillary artery, with foci of high signal intensity on T1-weighted images suggesting fat, and with mild increased signal intensity on T2-weighted images and mild enhancement after gadolinium administration. There is a focal signal void representing a surgical clip in this region. This corresponds to a low density focus in the same location seen on chest CT dated 4/16/2016. Given its signal characteristics, relative lack of enhancement, and similarity in size to CT the study from April 2016, this could represent treated tumor or scar tissue, but we see no dominant nodular focus to confirm viable tumor recurrence or metastatic disease. The rotator cuff itself appears intact. There is perhaps minimal enhancement of the synovium of the glenohumeral joint, which may reflect prior radiation therapy, but we see no joint effusion. We see no bone marrow signal abnormalities.
Post-therapy changes of sarcoma resection and radiation as described above. An amorphous collection of heterogeneous signal anterior to the subscapularis along the lateral margin of the axillary artery likely corresponds to a low density collection on CT scan dating back to April 2016 and could conceivably reflect treated tumor, but we see no dominant nodular focus to confirm viable tumor recurrence or metastatic disease.