The pleura in health and disease.

A wide variety of local, regional, and systemic diseases may have pleural manifestations. The scope of this pathology encompasses a wide spectrum ranging from minimal inflammatory changes to highly malignant neoplasms. An overview of the normal structure of the pleura is provided, along with the diseases that may be encountered. Pleural specimens from patients with pneumothorax are rarely encountered by pathologists. In contrast, pathologists frequently receive pleural specimens showing evidence of inflammation, repair, or neoplasm. In these circumstances, an awareness of less common (and often clinically highly important) conditions such as epithelioid hemangioendothelioma and primary pleural malignant mesothelioma is essential. Knowledge of the clinical setting (e.g., disease tempo) and radiological picture (e.g., laterality) is often of great value to the pathologist in arriving at a correct diagnosis. Similarly, knowledge of the normal anatomical considerations and familiarity with the expected pleural histopathology for the most clinically relevant pleural diseases are critical assets for pulmonary physicians in providing optimal care for their patients.