A Case of Pulmonary Artery Sarcoma Presented as Cavitary Pulmonary Lesions
An 18-year-old man was referred to our institution from a primary clinic for further evaluation and management of cavitary pulmonary lesions. He had no significant medical history and had visited the primary clinic 3 months before he was referred to our institution. He presented with complaints of cough, blood-tinged sputum, and right chest wall pain. The initial chest radiography at the primary clinic showed patchy consolidations in the right upper lobe (), and non-enhanced chest CT was performed. A 5-cm cavitary consolidation and multifocal nodular consolidations were observed in the right lung, mainly in the right upper lobe posterior segment and the right lower lobe (). The patient was treated with medication, including empirical antibiotics, and follow-up non-enhanced chest CT was performed every month for the next 3 months. Despite medical treatment, his symptoms did not improve and the lung parenchymal lesions persisted. Follow-up CT showed changes in the pulmonary lesions, decrease in the size of the main cavitary consolidation and increase in the number and size of adjacent nodular consolidations (). Eventually, the patient was referred to our institution for further diagnosis and treatment.\nWe suspected the possibility of various conditions that can cause cavitary lesions, including bacterial infection, fungal infection, tuberculosis, autoimmune disease, vasculitis, malignancy, and other rare diseases. The findings of laboratory examinations were unremarkable. The patient's leukocyte count was 7,870/µL with a C-reactive protein level of 0.44 mg/dL. We could not detect any microorganisms on the microbiologic studies including sputum culture, acid-fast bacilli stain, interferon-gamma release assay and aspergillous antigen test. The tests of autoantibodies such as antinuclear antibody and antineutrophil cytoplasmic antibody were negative. Further, no endobronchial lesion was observed on bronchoscopy. Percutaneous needle aspiration was performed, targeting the cavitary consolidation of the right upper lobe, but the pathologic results were unremarkable. Pathology examination showed parenchymal necrosis and fibrosis, interstitial lymphocytic infiltration, and type II pneumocyte hyperplasia. We did not detect granuloma, evidence of vasculitis, or any other possible causes of the pulmonary lesions.\nNext, the patient underwent contrast-enhanced chest CT, which showed a filling defect within the lumen of the right interlobar pulmonary artery, raising the possibility of either pulmonary thromboembolism or PAS (). The patient received low molecular weight heparin, considering the possibility of pulmonary thromboembolism. Deep vein thrombosis was not detected on venous duplex examination of the lower extremities. Positron emission tomography (PET)-CT with 18F-fluorodeoxyglucose (FDG) showed increased FDG uptake, with a maximum standardized uptake value of 9.6 along the right interlobar pulmonary artery, suggesting the presence of a malignant lesion ().\nTo confirm the diagnosis, open thoracotomy and excisional biopsy were performed. At surgery, frozen biopsy specimens obtained from the right interlobar pulmonary artery revealed a PAS. Accordingly, the patient underwent subsequent curative right pneumonectomy.\nGrossly, a 1.5×1 cm gray-tan soft tumor was detected in the lumen of the right interlobar pulmonary artery (). The distal pulmonary artery was occluded with thrombus. A gray-tan-yellow infarct, measuring 4×2×2 cm, was observed in the right upper lobe, and multiple, small gray-tan nodules were scattered in the remaining lung.\nHistopathologic examination of the intravascular tumor revealed abundant spindle cells with high cellularity, frequent mitoses, and nuclear pleomorphism (). Immunohistochemical staining was positive for smooth-muscle actin and desmin (). Staining for CD34 and CD56 was negative. Pathologic finding of the distal parenchymal lesions were ischemic necrosis and fibrosis, indicated pulmonary infarct. Also, there were hematogenous spread of occlusive tumor emboli and multiple parenchymal involvements within the right lung.\nThe patient recovered uneventfully and received 3 cycles of adjuvant chemotherapy with ifosfamide and doxorubicin. However, treatment was terminated because of side effects, which included severe gastrointestinal symptoms and neutropenia. There was no evidence of local recurrence or distant metastasis 6 months after surgery.