A 51-year-old man was admitted to the hospital with a diagnosis of a left lung nodule for 1 month. The patient reported a history of cough and hemoptysis 1 month previously, at which time a chest CT scan showed a nodule in the left lung hilum accompanied by calcification ( Figure 1A ), which was initially diagnosed as pulmonary tuberculosis; this patient then received anti-tuberculosis treatment and was discharged after improvement. To exclude the possibility of malignancy, the patient underwent a chest CT scan again, and multiple nodules partly accompanied by calcification in the left lung parenchyma, an enlarged high-density mass compared to that on the previous scan in the hilum of the left lung and pleural effusion were observed ( Figures 1B, C ). The contrast-enhanced CT scan and three-dimensional volume rendering image revealed that the large high-density mass in the left hilum invaded the adjacent left pulmonary artery and vein and bronchus of the upper lobe ( Figures 1D-F ). On bronchoscopy, the bronchus mucous membrane of the left upper lobe was swollen and congested, accompanied by mucosal protrusion and lumen stenosis ( Figure 1G ). The patient had a history of diabetes and lost 4 kg of weight in the recent 1 year. There were no other abnormalities reported by the patient in terms of medical history, and the physical examination and laboratory tests were normal. After routine antibiotic treatment for 1 week, the patient progressed and developed symptoms of chest pain and tightness, shortness of breath, and recurring orthopnea, which resulted in respiratory insufficiency. Therefore, left pneumonectomy under cardiopulmonary bypass was performed.
Intraoperative exploration confirmed the CT findings and detected a giant and hard mass in the left lung hilum, and the tumor occluded the adjacent left pulmonary artery and vein lumen. The pathological examination showed that the tumor tissue involved the whole left lung, but there was no evidence of pleural involvement, positive bronchial margins, or local lymph node metastasis ( Figure 1H ). Immunohistochemical analyses revealed that the tumor cells were positive for vimentin and Ki67 but negative for AE1/AE3, CD34, S-100, and EMA. The final diagnosis was primary extraskeletal osteosarcoma in the left lung and pulmonary artery. The patient refused to receive chemotherapy and radiotherapy after the operation and was discharged after 1 month of symptomatic and supportive treatment. Four months after the operation, a contrast-enhanced CT scan demonstrated tumor recurrence in the left hilum and multiple metastases in the left pleura and somatic muscles, which showed high concentrations of radioactivity on 99mTc-MDP SPECT/CT examination ( Figure 2 ). Then, the patient received a course of systemic chemotherapy with epirubicin, cisplatin, and ifosfamide. Six months after the operation, a contrast-enhanced CT scan revealed enlargement of the recurred local tumor and metastases, especially the lesion at the left hilum, causing compression of the adjacent esophagus ( Figure 3 ).
(A-C) Contrast-enhanced CT scan showing that the tumor recurred in the left lung hilum with multiple metastases in the left pleura and somatic muscles (blue arrows).