Good Vibrations and the Power of Positron Thinking: Positron Emission Tomography and Endoscopic Ultrasound in Staging of Mesothelioma—Two Case Reports

A 55-year-old electrician, smoker, presented with breathlessness and dysphagia. He was found to have a pleural effusion on chest radiograph, and underwent video-assisted thoracoscopic surgery. This revealed pleural deposits, which were biopsied and showed malignant mesothelioma of epithelioid subtype. He had a talc pleurodesis performed. In view of the dysphagia, he had an esophagastroscopy, with no obvious abnormality found. Because of consideration for extrapleural pneumonectomy surgery, in the context of the national MARS trial, a positron emission tomography (PET)/computed tomography scan was performed, which demonstrated intense uptake in the left pleura, and less intense uptake in the posterior mediastinum in the region of the esophagus (Figure 1). He then underwent a mediastinoscopy, which found malignant mesothelioma in a mediastinal lymph node, and nondiagnostic tissue from the subcarinal mass. His dysphagia continued, and the subcarinal mass dramatically increased in size (Figure 2). He therefore underwent a further endoscopy with endoscopic ultrasound. A stenosis of the esophagus was seen at 30 cm with edematous mucosa, and under endoscopic ultrasound a circumferential mass between 28 and 40 cm was observed, with a maximal thickness of 23 mm. Biopsies of the esophageal wall confirmed malignant mesothelioma. Over the next few weeks, the dysphagia increased, leading to esophageal stent insertion (Figure 3) with symptomatic improvement.

A 60-year-old nonsmoking man, with no obvious history of exposure to asbestos, presented with malaise, dyspnea, and weight loss. Chest radiograph demonstrated a left sided pleural effusion. A video-assisted thoracoscopic surgery pleurodesis was performed, and biopsies of pleural deposits demonstrated mesothelioma of mixed epithelioid and sarcomatoid histology. Staging computed tomography showed circumferential thickening over the left hemidiaphragm and mediastinum. There was no significant central lymphadenopathy, and no evidence of disease outside the left hemithorax. He had port site radiotherapy, then received six cycles of three- weekly chemotherapy with cisplatin [75 mg/m² intravenously (IV) day 1] and pemetrexed (500 mg/m² IV day 1) with stable disease as best objective response. He was subsequently considered for extrapleural pneumonectomy, and had a PET scan, which demonstrated fluoro-deoxy glucose (FDG) uptake in the left hemithorax, no uptake in the mediastinum, but an unexpected intense focus of uptake (standard uptake value 4) in celiac nodes (Figure 4). On review, the patient had developed epigastric pain, and had undergone a diagnostic esophagogastroscopy, which demonstrated no abnormalities. An endoscopic upper gastrointestinal ultrasound was performed, and enlarged celiac nodes with abnormal ultrasonographic morphology were noted. Fine-needle aspiration of one of the enlarged nodes confirmed metastatic mesothelioma. Extrapleural pneumonectomy was therefore not considered feasible. A subsequent PET scan performed before consideration of palliative decortication demonstrated significant progression both of the primary disease and locoregional and celiac axis nodes.