Subpleural micronodular pattern at CT and radiopathologic correlation

Transcription

1 Subpleural micronodular pattern at CT and radiopathologic correlation Poster No.: C-0876 Congress: ECR 2012 Type: Educational Exhibit Authors: G. Cabrera, E. Romá de Villegas, M. L. Domingo, C. P Fernandez Ruiz, V. Cortés Vizcaino, J. Vilar ; Valencia/ES, 2 IBIZA, sp/es Keywords: CT-High Resolution, CT, Thorax, Respiratory system, Biopsy, Inflammation, Infection, Neoplasia DOI: /ecr2012/C-0876 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 14

2 Learning objectives To review all thoracic diseases which may associate subpleural parenchymal micronodules; to describe and classify these subpleural and perifissural small nodules according to their differential CT imaging features and show their pathologic correlation Background Parenchymal subpleural micronodules are observed with high frequency in pulmonary lymphangitic carcinomatosis, pneumoconiosis, and sarcoidosis but also can be found in about 14% of healthy Adults although situated predominantly in the upper lung zones. A particular subtype of subpleural nodules are perifissural nodules which tend to be benign even in patients with the highest risk factors for lung cancer. In pulmonary sarcoidosis, granulomas have a characteristic distribution in relation to lymphatics in the peribronchovascular interstitial space, but also subpleural interstitial space, and, to a lesser extent, the interlobular septa. Pneumoconiosis is caused by the accumulation of inhaled particles and involves a reaction of tissue in the lung, may be clinicopathologically classified as fibrotic (involving focal nodular or diffuse fibrosis) or nonfibrotic (involving particle-laden macrophages, with minimal or no fibrosis). Imaging findings OR Procedure details Sarcoidosis Sarcoidosis is a multisystem chronic inflammatory condition of unknown etiology. It is characterized by noncaseous epithelioid cell granulomas and changes in tissue architecture, which may affect almost any organ. Although the age of presentation is very broad, sarcoidosis most commonly affects patients between 20 and 40 years of age. Involvement of the lung and the mediastinal and hilar lymph nodes is most common, being seen in approximately 90% of patients, and accounts for most of the morbidity and mortality associated with the condition. Page 2 of 14

3 Granulomas in the lung parenchyma have a characteristic distribution in relation to lymphatics in the peribronchovascular interstitial space, subpleural interstitial space, and, to a lesser extent, the interlobular septa (ie, a lymphangitic distribution). Fig. 1: Figure 1. Pulmonary Sarcoidosis. A.. Subpleural micronodules (arrow) some peribronchial nodules (dotted arrow) and bilateral hiliar lymphadenopathies. B. Characteristic sarcoid noncaseating granulomas with giant cells in pulmonary sarcoidosis. Hyaline fibrosis scar is seen between the granulomas. Fig. 2: Figure 2. Pulmonary sarcoidosis. Coalescent peribronchial nodules nodules formig masses. Subpleural nodules are also seen. Page 3 of 14

4 Fig. 3: Figure 3. Coalescence of granulomas produces small nodules that are palpable or visible as 1 to2 cm, noncaseating, noncavitated consolidations. Histologically, the lesions are distributed primarily along the lymphatics, around bronchi and blood vessels, although alveolar lesions are also seen. Airways disease Filled airways appear as subpleural nodules in the periphery, and these can be indistinguishable from other causes of subpleural nodules, such as sarcoidosis or hematogenous metastases. Finding evidence of small airways disease elsewhere in the lung can suggest it as the cause of the subpleural nodules. Infections that spread along the endobronchial route, such as tuberculosis, aspiration pneumonia, and viral pneumonia can give rise to direct signs of small airways disease. Page 4 of 14

5 In smokers subpleural nodules have upper lobe predominance similar to that of respiratory bronchiolitis and almost certainly represent diseased small airways. Respiratory bronchioles correspond to the transition from bronchioles with columnar epithelium to alveolar ducts and alveoli with squamous epithelium. In Obliterative Bronchiolitis there is a concentricluminal narrowing of the membranous and respiratory bronchioles as a result of submucosal and peribronchiolar inflammation andfibrosis without any intraluminal granulation tissue or polyposis. There is an absence of diffuse parenchymal inflammation. On the other hand Cryptogenic Organizing Pneumonia is characterized by the presence of polyps of granulation tissue (Masson bodies) in the distal airspaces which may cause secondary bronchiolar occlusion due to extension of the inflammatory process. Page 5 of 14

6 Fig. 4: Figure 4. Subpleural nodules in patient with centroacinar emphysema secondary to smoking. Fig. 5: Figure 5. Subacute hypersensibility pneumonitis. Ill-defined subpleural and centrilobular nodules with lower lung predominace. Some patchy areas of ground glass opacities and consolidation in middle lobe. Page 6 of 14

7 Fig. 6: Figure 6. Miliar tuberculosis. A and B Correlation between plain chest film and CT. Tiny well defined nodules without lymphadenopathy or pleural effusion. Page 7 of 14

8 Fig. 7: Figure 7. Alveolar microlithiasis Diffuse bilateral deposition of intra-alveolar microliths with subpleural predominance. Microliths are hyperdense micronodules that look like sand grains of less than 3 mm Pulmonary Metastasis Radiologic findings of atypical pulmonary metastasis include multiple peripherally located round variable-sized nodules (hematogenous metastasis) and diffuse thickening of the interstitium (lymphangitic carcinomatosis). Page 8 of 14

9 Fig. 8: Figure 8. Lymphangitic carcinomatosis. A and B. Permeation of lymphatics by neoplastic cells from an adenocarcinoma of stomach. Nodular thickening of interlobar septa and bronchovascular bundles. C. Macroscopic specimen with interlobar septa thickening due to lymphatic vessels occupation (arrow). D. Histology shows metastasis within the lymphatic vessel in the subpleural interstitium. Rheumatoid Arthritis Pulmonary manifestations are relatively common in rheumatoid arthritis and tend to develop later in the disease as is also the case for many of its non-articular manifestations. Although RA is more common in women, respiratory disease more commonly develops in men. Page 9 of 14

10 Several forms of associated pleuropulmonary disease have been described including pleural effusion or pleuritis, rheumatoid lung nodules, Caplan syndrome, fibrosing alveolitis, lymphoid hyperplasia with germinal centers, pulmonary hypertension, and constrictive bronchiolitis. In addition to parenchyma nodules, subpleural nodules of variable size correspond to rheumatoid nodules. Pneumoconiosis The pneumoconiosis encompass a broad group of lung diseases which result from inhalation of various dust particles. The offending agents are mainly mineral dusts. They can be broadly classified as fibrotic or non fibrotic. Silicosis, coal worker pneumoconiosis, asbestosis, berylliosis, and talcosis are examples of fibrotic pneumoconiosis. Siderosis (iron oxide), stannosis (tin oxide), and baritosis (barium sulfate) are nonfibrotic forms of pneumoconiosis. Silicosis nodules are seen distributed diffusely throughout both lungs, but predominantly in the upper lobe. At thin-section CT, nodules are usually centrilobular, paraseptal, and subpleural with a perilymphatic distribution. Subpleural nodules have a rounded or triangular configuration, and if they are confluent, they may resemble pleural plaques. Pulmonary tuberculosis occurs in 25% of patients with acute or classic silicosis. Page 10 of 14

11 Fig. 9: Figure 9. Silicosis. A. Small nodules with a perilymphatic distribution with calcification of lymph nodes. B. Image obtained with polarized light shows silica particles Fig. 10: Figure 10. Silicosis. A and B. Multiple small nodules that are upper lobe predominant without eggshell calcifications. Berylliosis, a chronic granulomatous lung disease caused by exposure to beryllium dust or fumes, is characterized by the accumulation of CD4-T cells and macrophages in the lower respiratory tract. Exposure to beryllium may occur in ceramics manufacture, nuclear weapon production, and aerospace industry. Depending on the severity of the immunity response to beryllium inhalation, noncaseating granulomas may form and, eventually, fibrosis may occur in the lungs. Granulomas in berylliosis are histopathologically Page 11 of 14

12 indistinguishable from those in other granulomatous disorders, such as sarcoidosis. Hilar lymph node enlargement also is frequently present, but it is moderate, compared with that observed in sarcoidosis Fig. 11: Figure 11. Berylliosis. Conglomerate masses and fibrosis in upper lobes Page 12 of 14

13 Fig. 12: Figure 12. Berylliosis. A. Subpleural and parenchymal small nodules distributed along bronchovascular bundles. Interlobular septal thickening and bronchial wall thickening with hiliar and mediastinal lymphadenopathy. B. Masson's trichrome staining showing collagen fibers of fibrosis and granulomas. Conclusion There is a wide spectrum of pulmonary diseases presenting with subpleural nodules, many of them are granulomatous processes of distinct etiology. Others nodules are associated to disorders in the airways or are due to accumulation of foreign substances such as dust and fumes within alveolar macrophages. Subpleural nodules without other associated findings can be found in healthy individuals or smokers and lack of malignant potential. Personal Information Gerardo Cabrera Orozco Servicio de Radiodiagnóstico Hospital Universitario Doctor Peset Avenida de Gaspar Aguilar, 90 Page 13 of 14

14 46017 Valencia, Spain References Ahn MI, Gleeson TG, Chan IH, McWilliams AM, Macdonald SL, Lam S, Atkar-Khattra S, Mayo JR. Perifissural nodules seen at CT screening for lung cancer. Radiology Mar;254(3): Chong S, Lee KS, Chung MJ, Han J, Kwon OJ, Kim TS. Pneumoconiosis: comparison of imaging and pathologic findings. Radiographics JanFeb;26(1): Review. Remy-Jardin M, Beuscart R, Sault MC, Marquette CH, Remy J. Subpleural micronodules in diffuse infiltrative lung diseases: evaluation with thin-section CT scans. Radiology Oct;177(1): Remy-Jardin M, Remy J, Cortet B, Mauri F, Delcambre B. Lung changes in rheumatoid arthritis: CT findings. Radiology Nov;193(2): Seo JB, Im JG, Goo JM, Chung MJ, Kim MY. Atypical pulmonary metastases: spectrum of radiologic findings. Radiographics MarApr;21(2): Review Teel GS, Engeler CE, Tashijian JH, ducret RP.Imaging of small airways disease. Radiographics Jan;16(1): Review. Kim KI, Kim CW, Lee MK, Lee KS, Park CK, Choi SJ, Kim JG. Imaging of occupational lung disease. Radiographics Nov-Dec;21(6): Review. Page 14 of 14