Metabolic Imaging of Malignant Pleural Mesothelioma With Fluorodeoxyglucose Positron Emission Tomography: Differences between FDG-PET imaging

Two cases in which the differences between FDG-PET imaging and other procedures are well illustrated are described in detail. In one case (case A), a 46 year-old man reported several episodes of bronchitis and pneumonia. He developed a large left pleural effusion. A thoracentesis did not reveal the presence of malignant cells. A CT scan revealed several pleural implants on the left, enlarged nodes in the preaortic and right paratracheal areas, and abnormal right posterior pleural thickening. The FDG-PET scan revealed extensive pleural involvement in the left, but no evidence of disease in the right hemithorax or in the mediastinum. Thoracoscopy and mediastinoscopy confirmed the PET findings. In a second case (case B), a 56-year-old former shipyard worker complained of progressive shortness of breath, frequent upper respiratory tract infections, and cough. A chest radiograph revealed left pleural thickening with asbestos-related pleural changes in the right. A CT scan revealed marked pleural thickening with loculated fluid in the posterior left base with scattered pleural thickening and pleural calcifications on the right and no mediastinal adenopathy. The PET study revealed a diffuse increase in the metabolic activity in the pleura at the base of the left lung, with increased tracer uptake along the diaphragm, the mediastinal pleura, and in lymph nodes in the mediastinum. Bronchoscopy, mediastinoscopy, and thoracoscopy were attempted to obtain biopsy specimen and stage the extent of the disease. The bronchoscopy did not reveal evidence of malignancy. Mediastinal biopsy specimens revealed granulomatous lymphadenitis in several nodes with no evidence of malignancy. The thoracoscopy tube could not be inserted in the pleural space due to adhesions, so a minithoracotomy was performed for pleural biopsy. Histologic examination of several biopsy sites revealed dense fibrous connective tissue, consistent with pleural plaques. Since all the biopsy specimens were negative for malignancy, the patient was discharged from the hospital and followed up clinically. Four months later, because of progressive shortness of breath and chest pain, a left parietal pleural decortication with a left thoracoscopy were performed. The histopathologic analysis of the chest wall and parietal pleural peel demonstrated the presence of a biphasic malignant mesothelioma.

Category: Pulmonary Function

Tags: FDG, malignant mesothelioma, metabolic imaging, positron emission tomography