Tumors of the pleura are most commonly secondary to metastases. Primary pleural tumors are quite uncommon and thus pose a diagnostic and therapeutic dilemma to the thoracic surgeon. The most common primary tumor of the pleura is malignant pleural mesothelioma (MPM). There has been improvement in the survival of these patients but owing to the complexity and spectrum of treatment options, diagnosis and management of patients with MPM remain a difficult task for the thoracic surgeon. In contrast, malignant pleural effusions (MPEs) are one of the most common problems a thoracic surgeon will see. Timely diagnosis as well as optimal treatment is crucial for the palliation of the patient with advanced disease.
The anatomy and physiology of the pleura and pleural space are described and illustrated in Chap. 106. Briefly, each lobe of the lung is covered by a thin double-layered sac called the pleura that covers the lung and lines the chest wall, diaphragm, and mediastinum (Fig. 99-1). The internal surface of the sac is called the visceral layer, and it lies adjacent to the lung surface; the external surface is known as the parietal pleura, and it lies adjacent to the chest wall, diaphragm, and mediastinum. Each pleural membrane is composed of five distinct layers (Fig. 99-2; see also Chap. 109). The internal-most layer consists of a monolayer of mesothelial cells, and the space between is defined as the pleural space. The lymphatic drainage of the pleural space depends on the subpleural lymphatic networks of both the parietal and visceral pleurae (Fig. 99-3).
Cross-sectional anatomy of the thorax, with attention to the relationship between the parietal and visceral pleura, as well as the chest wall, lung, and mediastinum. A. Coronal view. B. Axial view
Histologic layers of the parietal and visceral pleurae. Note the presence of stomata only in the parietal pleura.
Illustration depicting subpleural lymphatics and drainage pathways to the mediastinal and internal mammary chains. A. Parietal pleura. B. Visceral pleura.
Primary pleural malignancies are very rare tumors (Table 99-1). MPM is the most common primary pleural tumor. Approximately 2000–3000 new cases occur annually in the United States.1 Exposure to asbestos has long been linked to the development of MPM.2 Despite the widespread ban on asbestos use since the early 1970s, the incidence of MPM has increased steadily since the 1960s and is not expected to peak until 2020.3 Diagnosis of MPM is often delayed, resulting in a poor prognosis. With the acceptance of multimodality therapy, better outcomes have been reported, especially in a subset of patients with favorable prognostic factors. MPM remains a ...