대한흉부영상의학회 Korean Society of Thoracic Radiology

Discussion

Diagnosis With Brief Discussion

Diagnosis

Tumor Embolism Caused by Chondroblastic Osteosarcoma

Radiologic Findings

She was diagnosed as chondroblastic osteosarcoma in the left knee two years before. Neoadjuvant chemotherapy, wide excision, and tumor prosthesis were performed.
Chest radiograph shows nodular opacity in the right upper lobe. Patchy areas of consolidation are seen in the left lung. Contrast-enhanced CT scan shows a filling defect in the left lower lobe artery as a result of an embolus. At lower level, multifocal patchy consolidations are seen in the left lower lobe. A filling defect in the left upper pulmonary artery and a metastatic nodule in the right upper lobe were also seen (not shown). Multiple perfusion defects in the left lower lobe and lingular segment of the left upper lobe were observed in the perfusion lung scan.

Left lower lobectomy and wedge resection of both upper lobes were performed. Thrombus from left pulmonary artery was proved as a tumor thrombus and it appeared as a branching tree. The nodule in the right upper lobe was proved as a metastatic nodule. Patchy consolidations in the left upper and lower lobes were proved as organizing pneumonia.

Brief Review

Tumor emboli sufficiently large to be hemodynamically significant are sometimes encountered and can on occasion be the presenting feature of the neoplastic disease. They occlude small pulmonary vessels and can give rise to severe dyspnea, which usually develops over a matter of days but sometimes builds up over several weeks. Pleuritic chest pain is relatively common, and fatigue, weight loss, cough, hemoptysis, and syncope are seen in a few patients.
On physical examination most patients show signs of right ventricular overload, but just as with pulmonary thromboembolism there may be relatively few respiratory findings. The condition differs from widespread, blood-borne metastases in that a metastasis represents tumor that has invaded the vessel wall and acquired its own blood supply. Tumor emboli are clumps of cells that are lodged within the lumen of the pulmonary vessels and have not yet invaded the vessel wall but are acting as obstructing emboli similar to thromboemboli. The patients are hypoxemic, have increased alveolar-arterial oxygen gradients, and have pulmonary arterial hypertension. The primary tumors frequently associated with tumor embolism are hepatoma, breast and renal carcinoma, gastric and prostate cancers, and choriocarcinoma. The diagnosis of pulmonary endovascular choriocarcinoma in young female patients is important because it is potentially curable with chemotherapy. Pulmonary tumor embolism with osteosarcoma is an unusual phenomenon that has rarely been reported.
The plain chest radiographs are usually normal. Pulmonary arterial hypertension is rarely recognizable. A few patients show nonspecific pulmonary shadows. Radionuclide lung scans show multiple, small, peripheral, subsegmental perfusion defects with a normal ventilation scan. Pulmonary angiography shows delayed filling of segmental arteries, reduction in number of branch vessels, and occasionally 1 to 2 mm filling defects.
The mortality of the condition is very high, and the role of intervention is not clear. Surgical resection of the primary tumor without specific treatment of the emboli has been attempted and good results have been claimed. Whether these emboli will respond to chemotherapy has not yet been investigated.

References

1. Hansell DM, Peters AM. Pulmonary vascular diseases and pulmonary edema. In: Amstrong P, Wilson AG, Dee P, Hansell DM eds. Imaging of diseases of the chest. 2nd ed. Mosby 1995:393
2. Fraser RS, Pare JAP, Fraser RG, Pare PD. Neoplastic diseases of the lung. In: Fraser RS, Pare JAP, Fraser RG, Pare PD, eds. Synopsis of diseases of the chest. 2nd ed. Philadelphia: Saunders 1994:525
3. Ahmed AA, Heller DS. Fatal pulmonary tumor embolism caused by chondroblastic osteosarcoma: report of a case and review of the literature. Arch Pathol Lab Med. 1999; 123:437-440

Keywords

Lung, Vascular, Malignant tumor, embolism,