Type:
Educational Exhibit
Keywords:
Lung, Mediastinum, Respiratory system, Thorax
Authors:
B. Feragalli, V. Di Mizio, F. De Filippis, R. L. Patea, L. Guetti, M. L. Storto; Chieti/IT
DOI:
10.1594/ecr2010/C-0890
Background
Malignant Pleural Mesothelioma (MPM) is the most common primary neoplasm of the pleura that typically affects individuals occupationally exposed to asbestos through a variety of industries. This tumor has emerged in significant numbers of patients during the last 30 years in the industrialized countries. Because of the latency period, and continued asbestos use in the 1970s, its incidence is likely expected to reach a higher peak between years 2010 and 2030.
MPM are generally divided into three histologic categories: epithelioid, sarcomatoid and biphasic. Epithelioid mesothelioma constitutes approximately 55-65% of malignant mesotheliomas and the sarcomatoid variant constitutes approximately 10-15%; the remaining mesotheliomas (20-35%) fall into the biphasic category, which evinces features of both epithelioid and sarcomatoid mesotheliomas.
MPM is a usually fatal primary neoplasm. The diagnosis of this neoplasm is often made at a late stage and the prognosis is still very poor with a median survival from diagnosis of under a year with supportive care alone. However, recent studies have shown an improved survival after multimodality therapy consisting of extrapleural pneumonectomy followed by radiation and chemotherapy. In selected patients with epithelioid histology and no extrapleural lymph node metastases, results have shown an increase in survival of up to 51 months.
This surgery entails resection of the pleura, the pericardium and the diaphragm in addition to the whole lung on that side. Surgery is generally not performed in sarcomatous variants.
Early diagnosis and an accurate selection of patients that may benefit from this radical surgery is paramount. To this end, we must recognise the signs of limited MPM that allow the diagnosis of this neoplasm at its early stage and, for staging purposes, we have to be able to distinguish between a T3, a locally advanced but resectable tumour, and a T4, an unresectable tumour. Infact T3 describes a locally advanced tumor that is still amenable to surgical resection of all gross disease. In addition to involvement of all the pleural surfaces, there may be areas of tumor extension into the endothoracic fascia or the mediastinal fat. There may be a nontransmural involvement of the pericardium. A solitary, completely resectable focus of tumor extending directly into the chest wall is also included in the T3 category. This focus usually occurs in patients who have a tumor implant in the chest wall at the site of a previous diagnostic thoracentesis, pleural biopsy or thoracoscopy. On the other hand T4 designates a locally advanced and technically unresectable tumor. In addition to involvement of all the pleural surfaces, T4 is characterized by features including diffuse extension of tumor into the chest wall, direct extension through the diaphragm to the underlying peritoneum or direct extension to the controlateral pleura, the mediastinal organs, the spine, the myocardium or the internal surface of the pericardium.