Figure legends:
Figure 1: MR neurography: A spindled-shape space-occupying lesion adjacent to a peripheral nerve (a brachial plexus branch), near the anterior axillary line is detected. The lesion is heterosignal on fluid sensitive sequences (STIR: contains internal cystic-solid component). The ribs and chest wall subcutaneous soft tissue are intact. Above mentioned descriptions are more suggestive of peripheral nerve sheath tumor such as schwannoma.
Figure 2: Intraoperative view of the tumor: A well-circumscribed ovoid solid tumor with dark blue appearance.
Figure 3: Histomorphologic study shows sheets of atypical round blue cells with brisk mitotic figures and rosette formation (Hematoxylin and Eosin; x1000).
Figure 4: Immunohistochemistry study shows diffuse strong membranous staining for CD99; x1000 (A), diffuse strong cytoplasmic staining for NSE; x1000 (B), diffuse nuclear staining for FLI-1; x1000 (C), positive cytoplasmic staining for Synaptophysin; x1000 (D) and CD56; x1000 (E) in some tumor cells and positive cytoplasmic staining for CKAE1/3 in scattered tumor cells; x1000 (F)