OBSERVATION:

An 18-year-old woman who suffered from right basi-thoracic pain and appearance of a swelling at the level of the 10thright rib. Chest CT showed a heterogeneous hyper vascular mass, located on the 10th right rib and measuring 106 x 93 x 110 mm. The mass was heterogeneous with several sites of necrosis. There were osteolysis of the rib with bifocal cortical rupture. The mass was in a tight contact with the liver through the diaphragm, which was partially invaded. Surgical biopsy was performed. The mass was composed of small round cells with round uniform nuclei and PAS positive cytoplasm. Tumor cells demonstrate a diffuse membranous CD99 positivity. Desmin, myogenin, chromogranin, synaptophysin and keratin were negatives (Figure 1).
The diagnosis of Ewing’s sarcoma was made. The patient received 6 cycles of chemotherapy (Vincristine, Ifosfamide, Doxorubicin and Etoposide). A post therapy Chest CT-scan showed almost the same initial findings (figure 2). Surgical resection was indicated after multidisciplinary team discussion. Resection consisted on a total resection of the 10th right rib with sarcoma, partially extended to the 9th and 11th right ribs and to the diaphragm. There was no signs of direct extension to the liver. Chest wall repair was performed with a polypropylene mesh covered by a latissimus dorsi muscle flap (figure 3).
Postoperative course was uneventful. The pathological examination of the specimen showed a small cell proliferation with foci of lace-like osteoid production (Figure 4). Finally, the diagnosis of a 12cm SCO of the 10th right rib, infiltrating adjacent soft tissues, with 20% of tumor necrosis was established. Surgical margins were negative. Adjuvant chemotherapy with Methotrexate (12g/m2) was indicated after multidisciplinary concertation, in association with adjuvant radiotherapy (45Gy). Actually, the patient is well, with a good wound cicatrisation, and no signs of local recurrence.