Fig. 6.14 and 6.15). Figure 7-14 Traction bronchiectasis of usual interstitial pneumonitis in scleroderma. On HRCT, the term lung cyst refers to a thin-walled (usually < 2 mm), well-defined and circumscribed, air-containing lesion that is 1 cm or more in diameter (Fig. Diseases have zonal preferences in the lungs (Box 7-4), although severe diseases often become diffuse. 6.10 Silicosis. Most patterns can be readily identified on standard radiographs, but ground-glass and cystic disease patterns are much more readily appreciated on HRCT. Miliary, discrete (DD: tuberculomas that are larger than 5 mm and can calcify). Fig. Interstitial lung disease (ILD) describes a heterogeneous group of over 200 diseases affecting the pulmonary interstitium with varying degrees of involvement of the pleural space, airways, and pulmonary vasculature. In patients with isolated bronchiectasis, there are no other signs of lung disease. Often less evident in apices and bases. 6.2 Bronchiectases. Thickened interlobular septa (hexagons) and a fine reticular pattern are visible within the lobules. This opacification obliterates the pulmonary vasculature. Large masses of fibrous tissue seen centrally in the upper lobes are associated with traction bronchiectasis, Cystic abnormalities include honeycombing, traction bronchiectasis, lung cysts, and cavitary nodules. Figure 7-7 Septal thickening in lymphangitic carcinomatosis. Honeycombing is the only dependable radiographic sign of interstitial fibrosis. Fig. Confluent, diffuse consolidation and air bronchograms in both upper lobes can be seen in this example of an alveolar pattern in a patient with interstitial lung disease (i.e., sarcoidosis). Traditional interpretation of chest radiographs separates these processes into two groups: diseases that radiographically appear to involve the terminal airspaces or alveoli and those that appear to involve the interstitium. a Reticular pattern (Pneumocystis carinii pneumonia). A graphic or morphometric classification is a better approach and is enumerated in Box 7-3. The key-findings on the X-ray are: ill-defined homogeneous opacity obscuring vessels; Silhouette sign: loss of lung/soft tissue interface; Air-bronchogram; Extention to the pleura or fissure, but not crossing it; No volume loss; Chronic diseases are indicated in red. Interstitial lung disease is diagnosed radiographically when a reticular, nodular, or honeycomb pattern or any combination thereof is recognizable. (C) … Occasionally, lines that are 2.5 cm long and that outline more than one lobule can be identified, particularly in the periphery of the lung. Webb and colleagues describe such HRCT findings in interstitial lung disease further in their work (see Suggested Readings). Ill-defined nodules that are 6 mm to 1 cm in diameter may be associated with airspace consolidation around the peripheral bronchioles, particularly around the terminal bronchiole in the center of the secondary pulmonary lobule. Different kinds of Kerley lines are distinguished: Kerley A lines are straight lines measuring 2–6 cm in length and approximately 1 mm in thickness. Parenchymal consolidation, which has been referred to as alveolar or airspace disease, is characterized by dense opacification often with air bronchograms (Fig. Bilateral small nodules with preferential involvement of the mid and lower lung zones are seen in this arc welder that are not associated with hilar adenopathy or fibrosis and resolved after exposure was discontinued. Large masses of fibrous tissue may occur, usually in the central or axial interstitium (Fig. Although rare, they are classified with similar clinical, radiological, physiologic, or pathologic signs. congestive heart failure). 6.2). In the lower lobes, there are multiple, small, centrilobular ground-glass nodules. Idiopathic pulmonary fibrosis (usual interstitial pneumonitis). 6.2 Bronchiectases. Findings simulate sarcoidosis radiographically. Fig. Interstitial lung disease (ILD), or diffuse parenchymal lung disease (DPLD), is a group of respiratory diseases affecting the interstitium (the tissue and space around the alveoli (air sacs) of the lungs. d Ground-glass appearance produced by the summation of innumerable tiny retlculogranular densities (sarcoidosis). The complex world of interstitial lung disease presents nearly insurmountable challenges to the general surgical pathologist faced with a lung biopsy in this setting. Pneumoconioses and vascular disorders are discussed in Chapters 8 and 9. The term interstitial lung disease (ILD) (also called diffuse interstitial lung disease, fibrotic interstitial lung disease, pulmonary fibrosis, and pneumoconiosis) refers to a broad group of inflammatory lung disorders. The intralobular bronchiole often becomes visible when there is centrilobular thickening. 6.1a). Chest Radiology > Pathology > Interstitial Disease. Miliary and larger (up to 3 cm). Interstitial pulmonary fibrosis has many causes. Table 6.3 summarizes all disorders that demonstrate radiographically a diffuse reticular or reticulonodular pattern characteristic of interstitial lung disease. Acute Kerley lines are frequently associated with prominent interlobar fissures caused by subpleural edema. Density of the tiny nodules depends on the atomic number of the inhaled element. The posteroanterior view shows coarse linear opacities distributed more in the lower lungs than upper areas. Ill-defined nodules up to 1 cm in diameter are identified in both lungs. Honeycombing in idiopathic pulmonary fibrosis. A purely nodular pattern is found with the hematogenous spread of certain infections and tumors, but can also be encountered with other diseases (Table 6.1). They include distribution of disease, pleural abnormalities, the size of the lungs, the presence of pulmonary arterial hypertension, and mediastinal and hilar adenopathy. 6.1d) is caused by a hazy increase in lung density that is not associated with obscuration of underlying vascular markings. 7-7) is common in many interstitial lung diseases. Bronchiectases are often associated with loss of volume and crowding of the lung markings in the affected area together with compensatory overinflation of the spared lung (Fig. The nodular pattern (Fig. Honeycombing pattern in the usual interstitial pneumonitis of scleroderma. 7-14) is a phenomenon that occurs in the presence of severe lung fibrosis and distortion of lung architecture, in which the fibrous tissue produces traction on the bronchial walls, resulting in irregular bronchial dilation. Pattern that is predominant or usually associated with a specific disorder. The complex world of interstitial lung disease presents nearly insurmountable challenges to the general surgical pathologist faced with a lung biopsy in this setting. Interstitial nodules (Fig. Fig. b Kerley A lines (long arrows, touched up) and Kerley B lines (short arrows) (mitral stenosis). Note also the lytic involvement of the left fifth rib with pathologic fracture (arrow). They are most numerous at the base of the lungs. Mycoplasma and viral pneumonias can present in their early stages as localized interstitial diseases of fine reticular appearance before the extension of the inflammation into the air spaces causes a consolidation. 6.1e). This results in the appearance of large ring shadows. Multiple poorly defined nodules are seen bilaterally. In the peripheral lung, it appears as 1- to 2-cm lines that extend perpendicularly from the pleural surface into the substance of the lung. Prominence of the central dot (Fig. 6.1b). Diseases that cause a characteristic honeycomb pattern are summarized in Table 6.2. Pneumoconiosis caused by radiopaque dusts (iron, tin, barium, antimony and rare-earth compounds) (Figs. 6.1e). Figure 7-11 Airspace nodules in bronchioloalveolar carcinoma. Interstitial Lung Diseases . Interstitial lung disease (ILD) consists of a large and heterogeneous group of rare pulmonary disorders, characterized by abnormalities involving the alveoli and airway. 6.12 Siderosis. Figure 7-2 Linear opacities of nonspecific interstitial pneumonia. The six most common causes of diffuse interstitial pulmonary fibrosis are idiopathic (IPF, >50% of cases), collagen vascular disease, cytotoxic agents and nitrofurantoin, pneumoconioses, radiation, and sarcoidosis. Pneumoconiosis (inorganic dust) (e.g., silicosis, coal miner’s lung, berylliosis) (Figs. Often poorly defined, confluent nodules of varying size. Numerous nodules measuring only a few millimeters in diameter are present bilaterally, but are only shown for the right lower lung field. It is manifested by bronchial wall thickening and apparent enlargement of central pulmonary vessels. Most patterns can be readily identified on standard radiographs, but ground-glass and cystic disease patterns are much more readily appreciated on HRCT. This appearance is typical for silicosis and for coal worker’s pneumoconiosis, but it may also occur in end-stage sarcoidosis. In a given patient, they are relatively uniform in size and usually bunched together in grape-like clusters. 6 Interstitial Lung Disease. Acute or transient Kerley lines are usually found with hydrostatic pulmonary edema (elevated microvascular pressure caused by left ventricular failure, renal disease and fluid overload), and occasionally with pneumonia and pulmonary hemorrhage. More than 180 disease entities are characterized by acute, subacute, or chronic inflammatory infiltration of alveolar walls by cells, fluid, and connective tissue. It is often accompanied by other signs of interstitial lung disease, especially the patterns associated with reticular opacities and architectural distortion. This appearance is virtually diagnostic, although under very rare circumstances both pulmonary papillomatosis and paragonimiasis may mimic cystic bronchiectases. Figure 7-6 Axial interstitial thickening in a patient with sarcoidosis. 6.3 Bronchioloalveolar carcinoma. 6.8). Many diseases demonstrate more than one pattern (see Box 7-3). Pleural plaques, an uncommon feature, are produced almost exclusively by asbestos exposure. The standard chest radiograph remains the basic and, in some cases, the only imaging technique that is useful. Commonly, interstitial lung disease (ILD) presents with dyspnea on exertion, diffuse bilateral infiltrates on chest imaging, and restriction with diffusion impairment on physiologic testing. Finally, fibrotic scars may be the sequelae of virtually any disease capable of damaging the lung parenchyma severely enough. A subpleural line may be defined as a curvilinear opacity that is less than 1 cm from the pleural surface. Langerhans cell histiocytosis (eosinophilicgranuloma) (Fig. Pattern recognition in diffuse interstitial lung disease has been the subject of controversy for many years. Different kinds of Kerley lines are distinguished: Kerley A lines are straight lines measuring 2–6 cm in length and approximately 1 mm in thickness. Calcification occurs. Notice the dilated bronchus in the right upper lobe, Chronic Obstructive Pulmonary Disease and Asthma, Thoracic Radiology: Imaging Methods, Radiographic Signs, and Diagnosis of Chest Disease. 4 to 10 mm, poorly defined (early acute stage of disease). 7-7) is common in many interstitial lung diseases. Miliary and larger. The reticular pattern consists of a network of linear densities (Fig. Oily contrast material embolism (e.g., secondary to lymphography) (Fig. When these bronchiectatic segments become filled with retained secretion, they appear as homogeneous band-like densities (“gloved-finger” shadows). Thick-walled cystic spaces can be seen subpleurally in the bases. However, histiocytosis X and sarcoidosis in the early stages are usually associated with normal lung volumes, but lymphangioleiomyomatosis produces air trapping with large lung volumes. Chapter 56: Interstitial Lung Diseases. If left untreated, the inflammatory process can progress to irreversible pulmonary … Multiple small nodules are scattered throughout both lung fields. Findings related to emphysema and small airways disease (e.g., bronchiolitis, which may cause decreased lung opacity) are discussed in Chapters 10 and. A ground-glass appearance (Fig. congestive heart failure). Web Chapter 56. The posteroanterior view shows coarse linear opacities distributed more in the lower lungs than upper areas. The majority of interstitial lung diseases involve both lungs, or stated differently, the interstitial disease is usually diffuse, although some areas may be more affected and others more or less spared. In a given patient, they are relatively uniform in size and usually bunched together in grape-like clusters. Interstitial lung diseases (ILDs) encompass a wide range of diffuse pulmonary disorders, characterized by a variable degree of inflammatory and fibrotic changes of the alveolar wall and eventually the distal bronchiolar airspaces. Calcification extremely rare. Multiple small nodules of variable sizes are seen bilaterally, but are only shown for the right mid lung field. Coccidioidomycosis, blastomycosis, and Cryptococcosis (Fig. These diseases account for ∼15–20% of general pulmonary practice. In approximately 50% of cases, they are limited to one lung. More often, however, nodular and reticular patterns are combined in the same patient, resulting in a reticulonodular appearance of the interstitial disease. Some are primarily lung disorders, and some others are manifestations of diseases arising elsewhere. Lymphatic obstruction appears to be a major factor in the development of Kerley lines associated with malignancies (e.g., lymphangitic carcinomatosis, bronchogenic carcinoma, and lymphoma), since at least histologically, ipsilateral hilar involvement with tumor is almost invariably present under such conditions. Fibrosis due to collagen vascular disease, Some lymphangitic tumors (Kaposi’s sarcoma), Chronic interstitial pneumonias, idiopathic pulmonary fibrosis. Central septal lines outline the secondary pulmonary lobule, which appears as a polyhedral structure (thin arrow). Depending on the mesh size, one can distinguish between fine, medium, and coarse reticular patterns, although this distinction has no obvious differential diagnostic significance. Cystic bronchiectases may produce a radiographic picture similar to honeycombing. 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