• Non-Neoplastic Lung Diseases The cut surface of this lung demonstrates the typical appearance of a bronchopneumonia with areas of tan-yellow consolidation. Remaining lung is dark red because of marked pulmonary congestion. Bronchopneumonia is characterized by patchy areas of pulmonary consolidation. • Upon closer inspection, the pattern of patchy distribution of a bronchopneumonia is seen. The consolidated areas here very closely match the pattern of lung lobules. A bronchopneumonia is classically a "hospital acquired" pneumonia seen in persons already ill from another disease process. Typical bacterial organisms include: Staphylococcus aureus, Klebsiella, E. coli, and Pseudomonas. • A closer view of the lobar pneumonia demonstrates the distinct difference between the upper lobe and the consolidated lower lobe. Radiographically, areas of consolidation appear as infiltrates. At the left the alveoli are filled with a neutrophilic exudate that corresponds to the areas of consolidation seen grossly with the bronchopneumonia. This contrasts with the aerated lung on the right of this photomicrograph. • More virulent bacteria and/or more severe pneumonias can be associated with destruction of lung tissue and hemorrhage. Here, alveolar walls are no longer visible because there is early abscess formation. There is also hemorrhage. • Here is the gross appearance of a lung with tuberculosis. Scattered tan granulomas are present, mostly in the upper lung fields. Some of the larger granulomas have central caseation • At low magnification, this photomicrograph reveals multiple granulomas. • Seen in the pulmonary artery to the left lung on cut section is a large pulmonary thromboembolus. Such thromboemboli typically originate in the leg veins or pelvic veins of persons who are immobilized. Other contributing factors include trauma to the extremities, hypercoagulable states (Trousseaus's syndrome in patients with carcinomas; protein C or S deficiency; use of oral contraceptives), heart failure, pregnancy, and older age. • This is another form of obstructive lung disease known as bronchiectasis. Bronchiectasis occurs when there is obstruction or infection with inflammation and destruction of bronchi so that there is permanent dilation • The mid lower portion of this photomicrograph demonstrates a dilated bronchus in which the mucosa and wall is not clearly seen because of the necrotizing inflammation with destruction. This is the microscopic appearance of bronchiectasis. Bronchiectasis is not a specific disease, but a consequence of another disease process that destroys airways. • The chest cavity is opened at autopsy to reveal numerous large bullae apparent on the surface of the lungs in a patient dying with emphysema.Bullae are large dilated airspaces that bulge out from beneath the pleura.Emphysema is characterized by a loss of lung parenchyma by destruction of alveoli so that there is permanent dilation of airspaces. • Microscopically at high magnification, the loss of alveolar walls with emphysema is demonstrated. Remaining airspaces are dilated. • Another gross lesion typical for pneumoconio ses, and asbestosis in particular, is a fibrous pleural plaque. Seen here on the pleural side of the diaphragmati c leaves are several tanwhite pleural plaques. • A silicotic nodule in lung is seen here. It is composed mainly of bundles of interlacing pink collagen. There is a minimal inflammatory reaction • A pleural effusion occurs when fluid collects in the potential space between the parietal pleura on the lung and the visceral pleura on the chest wall. In this case, the fluid is red (serosanguinous), while the presence of clear fluid would be called a serous effusion. • Neoplastic Lung & Pleural Diseases • This is a squamous cell carcinoma of the lung that is arising centrally in the lung (as most squamous cell carcinomas do). It is obstructing the right main bronchus. The neoplasm is very firm and has a pale white to tan cut surface. • This is a larger squamous cell carcinoma in which a portion of the tumor demonstrates central cavitation, probably because the tumor outgrew its blood supply.Squamous cell carcinomas are one of the more common primary malignancies of lung and are most often seen in smokers. • In this squamous cell carcinoma at the upper left is a squamous eddy with a keratin pearl. At the right, the tumor is less differentiated and several dark mitotic figures are seen. • This is a peripheral adenocarcinoma of the lung. Adenocarcinomas and large cell anaplastic carcinomas tend to occur more peripherally in lung. Adenocarcinoma is the one cell type of primary lung tumor that occurs more often in non-smokers and in smokers who have quit. • The glandular structures formed by this neoplasm are consistent with a moderately differentiated adenocarcinoma. Peripheral lung cancers that have not metastasized can be easily resected. • This is another less common type of adenocarcinoma of lung known as a bronchioloalveolar carcinoma. Seen here is the multifocal variant that appears grossly (and on chest radiograph) as a pneumonic consolidation. Most of the upper lobe toward the right has a pale tan to grey appearance. • Microscopically, the bronchioloalveolar carcinoma is composed of columnar cells that proliferate along the framework of alveolar septae. The cells are well-differentiated. These neoplasms in general have a better prognosis than most other primary lung cancers. • Arising centrally in this lung and spreading extensively is a small cell anaplastic (oat cell) carcinoma. The cut surface of this tumor has a soft, lobulated, white to tan appearance. The tumor seen here has caused obstruction of the main bronchus to left lung so that the distal lung is collapsed. • This is the microscopic pattern of a small cell anaplastic (oat cell) carcinoma in which small dark blue cells with minimal cytoplasm are packed together in sheets. • Multiple variably-sized masses are seen in all lung fields. These tan-white nodules are characteristic for metastatic carcinoma. Metastases to the lungs are more common even than primary lung neoplasms simply because so many other primary tumors can metastasize to the lungs. • A nest of metastatic infiltrating ductal carcinoma from breast is seen in a dilated lymphatic channel in the lung. • The dense white encircling tumor mass is arising from the visceral pleura and is a mesothelioma. These are big bulky tumors that can fill the chest cavity. The risk factor for mesothelioma is asbestos exposure. • Mesotheliomas have either spindle cells or plump rounded cells forming gland-like configurations, as seen here microscopically. They are very difficult to diagnose cytologically.