Primary Ewing's Sarcoma of the Lung
A 41-year-old woman was admitted for hemoptysis of 4 days' duration. Her medical and family history was unremarkable. She visited a local clinic, where a chest radiograph revealed a radio-opaque mass in the right upper lung lobe. She was referred to Asan Medical Center. Computed tomography revealed several oval, smoothly marginated, and low attenuation lesions with ground-glass opacity in the right upper lung lobe (). Positron emission tomography with 18F-fluorodeoxyglucose (FDG) showed multiple round or oval lesions in the right upper lung lobe. The FDG uptake was increased in the lesions (maximal standard uptake value: 9.7) without any other abnormal uptake. She underwent bronchoscopy, and a transbronchial lung biopsy and wash with cytology were then performed. The pathological diagnosis of the specimen was a malignant small round cell tumor. Surgical resection was selected for definitive diagnosis and treatment.\nThe patient underwent right upper lobe lobectomy via posterolateral thoracotomy under one-lung ventilation. There were two relatively well-defined ovoid masses in the anterior and posterior segment of the right upper lobe (). These tumors were 5.5×5×3.5 cm and 4.5×4×3 cm in size, respectively. The cut surface was heterogeneously purplish, brown to yellowish, and pink in color. Focal hemorrhage and necrosis were evident. The tumors did not invade the visceral pleura. The surgical margins were not grossly involved. The small mass was approximately 3.3 cm from the bronchial resection margin, but the large mass abutted the bronchial margin. However, the remaining bronchus was too short to allow further resection, and the tumor was limited to the peribronchial soft tissue. Therefore, we decided to add radiation therapy.\nHistologically, the tumor was composed of uniform, small, round cells with indistinct borders. The tumor cells had scanty clear cytoplasm and round nuclei with fine chromatin. Immunohistochemical staining for CD 99 revealed diffuse membranous positivity in the tumor cells, which is a characteristic feature of Ewing's sarcoma (). Immunohistochemical staining for CD56, pancytokeratin, and leukocyte common antigen was negative for each.\nPostoperatively, the patient was transferred to the intensive care unit, and then, the next day, to the general ward. The chest tube was removed on postoperative day 2. She was discharged from the hospital on postoperative day 4, without any complications. At the outpatient clinic, the patient underwent 6 cycles of chemotherapy consisting of vincristine, doxorubicin, cyclophosphamide, ifosfamide, and etoposide. She also underwent radiation therapy. The patient received 50 Gy to the right hilum. She experienced no recurrence or distant metastasis for 4 years after the surgery.