Metastatic pleural tumor is caused by metastasis of tumor in other parts of the body to the pleura through the bloodstream or lymphatic pathways. Tumor, mainly lung cancer, breast cancer, and gastrointestinal tumor, in many parts of the body can metastasize to the pleura.
Clinical presentation and pathology
The main clinical manifestations are persistent, progressively aggravated thoracodynia, chest tightness, and progressive dyspnea. The main pathological changes are scattered, multiple metastatic nodules in the pleura, often accompanied by bloody pleural effusion, with rapid progression.
Imaging manifestations
X-ray
It is difficult to find small metastatic lesion on chest film. If the amount of pleural effusion is large, the metastatic lesion can be covered.
CT
Plain CT can only show large amounts of pleural effusion without apparent nodular lesion, scattered pleural nodules or irregular nodular thickening of the pleura can be seen in some patients, and enlarged lymph nodes in the mediastinum can be seen. Contrast-enhanced CT can show significant enhancement of pleural nodule.
Figure 1 Metastatic pleural tumor
a. Plain CT shows nodular thickening of the right pleura (↗), with homogeneous density; b. Contrast-enhanced CT shows homogeneous moderate enhancement, right pleural effusion, and enlarged right hilar lymph nodes.
MRI
Plain MRI is better than CT in visualization of pleural nodule. If accompanied by pleural effusion, the nodule is more apparent, particularly on T2WI. Contrast-enhanced MRI shows significantly enhanced pleural nodule.
Diagnosis and differential diagnosis
Metastatic pleural tumor is more common in pulmonary malignancies such as lung cancer. Generally, signs of pulmonary cancer can be seen, and diagnosis is not difficult. In pleural metastasis caused by primary malignant tumor in other parts, primary tumor can also be detected. If necessary, the diagnosis can also be determined based on pleural effusion cytology or pleural biopsy. This disease needs to be differentiated from diffuse pleural mesothelioma.