Malignant Pleural Mesothelioma

Radiologic-Pathologic Correlation

Abstract Introduction Etiology and Epidemiology of MPM Clinical Features Microscopic Features Characterization of MPM with Histochemistry, Immunochemistry, and Electron Microscopy

Gross Pathologic Characteristics Radiographic Features CT Features MR Imaging Findings Differential Diagnosis

Diagnostic Methods Staging and Resectability Treatment Prognosis Source Information References

Gross Pathologic Characteristics

MPM manifests most commonly as multiple tumor masses that involve the parietal and visceral pleural surfaces, with greater involvement of the parietal than the visceral layer (Figure 10). There may be a slightly higher incidence in the right hemithorax owing to the greater pleural surface area. The tumor may progress to thick sheetlike or confluent masses, with resultant lung encasement. Individual lobes may be encased in a thick rind by tumor growth along the fissures (Figure 11). Greater involvement of the inferior hemithorax is probably due to gravitational factors. A large pleural effusion is present in 60% of patients at diagnosis. Obliteration of the pleural cavity occurs later in the disease process. Chest wall and mediastinal involvement, including pericardial and cardiac invasion, may occur. Tumor growth along needle tracks and scars that penetrate the chest wall has been documented. The diaphragm is frequently invaded; tumor extension into the peritoneal cavity is identified in at least one-third of autopsies (Figure 12). Tumor spread across the mediastinum may result in involvement of the opposite pleural cavity.

Lymphatic and hematogenous metastases occur more frequently than previously supposed and are found at autopsy in more than half of MPM cases (46,47). The most frequently affected nodal site is the mediastinal lymph nodes, with occasional involvement of celiac, cervical, or axillary nodes. Hematogenous spread is most commonly reported in the lung, liver, kidneys, and adrenal glands (47). Metastases to bone, spleen, pancreas, intestines, brain, and thyroid have also been reported (35,47,48). Extensive bilateral lymphangitic spread rarely occurs in the pulmonary parenchyma (49).

Abstract Introduction Etiology and Epidemiology of MPM Clinical Features Microscopic Features Characterization of MPM with Histochemistry, Immunochemistry, and Electron Microscopy

Gross Pathologic Characteristics Radiographic Features CT Features MR Imaging Findings Differential Diagnosis

Diagnostic Methods Staging and Resectability Treatment Prognosis Source Information References