CT Signs of Solitary Pulmonary Lesions: Revisited

Transcription

1 CT Signs of Solitary Pulmonary Lesions: Revisited Poster No.: C-1764 Congress: ECR 2015 Type: Educational Exhibit Authors: H. Hayashi, K. Ashizawa, Y. Ogihara, A. Nishida, T. Tanaka, J. Fukuoka, M. Uetani ; Nagasaki/JP, 8501/JP Keywords: CT, Thorax, Lung, Contrast agent-intravenous, Cancer, Inflammation DOI: /ecr2015/C-1764 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 60

2 Learning objectives To understand the various CT signs and key findings of solitary pulmonary lesions. To know the pathological findings corresponding to these signs and findings. To understand the specific signs, combination of these signs and their limitations. Background There are many signs in chest CT, which we have been using in daily clinical practice. Some of them are derived from the findings in conventional chest radiography, and others are created originally based on the CT findings. These signs are useful to briefly describe the characteristics of the lesions, but it should be noted that the meaning or significance might not be the same as the original one. Contents Signs of internal structures air bronchogram (sign) angiogram sign CT halo sign reversed halo sign Signs of marginal characteristics spicula notch pleural indentation pit-fall sign Signs of specific lesions air crescent sign comet tail sign feeding vessel sign sarcoid galaxy sign Page 2 of 60

3 Findings and procedure details Signs of internal structures air bronchogram (sign) angiogram sign CT halo sign reversed halo sign Air bronchogram -chest radiograph- Fig. 1 on page 32 Phenomenon of air-filled bronchi being made visible by the opacification of surrounding alveoli. It is almost always caused by a pathologic airspace/alveolar processes, in which 1 something other than air fills the alveoli. Air bronchogram on chest radiograph is an important sign to describe a feature of airspace consolidation, but it is rarely used for nodular lesions. Page 3 of 60

4 Fig. 1: Pneumonia. Chest radiograph shows consolidation with air bronchogram. References: radiology, nagasaki university hospital - Nagasaki/JP Air bronchogram -CT- Fig. 2 on page 33 Fig. 4 on page 35 Page 4 of 60

5 Meaning of the air bronchogram on CT is slightly different from that on chest radiograph. The CT air bronchogram sign is not only seen in air space consolidation, but also in 2 solitary pulmonary nodules, more common in malignant than in benign ones. In small lung adenocarcinomas, AIS (adenocarinoma in site) and MIA (minimally invasive adenocarcinoma) are characterized by air containing structures, which are differentiating 3 features from invasive adenocarcinoma. However, focal organizing pneumonia also 4 shows air bronchogram or small bubble-like lucency in majority of the lesions. MALT lymphoma can also present as a nodule or consolidation with air bronchogram, which often simulates adenocarcinoma. Page 5 of 60

6 Fig. 2: Adenocarcinoma. Thin-section CT (TSCT) shows an "air bronchogram" running into the lesion. References: radiology, nagasaki university hospital - Nagasaki/JP Page 6 of 60

7 Fig. 3: Adenocarcinoma. Pathological microphotograh in low magnification view shows dilated bronchiole (arrow) entering into the tumor. References: radiology, nagasaki university hospital - Nagasaki/JP Page 7 of 60

8 Fig. 4: MALT lymphoma. TSCT shows an "air bronchogram" in the lesion. References: radiology, nagasaki university hospital - Nagasaki/JP Angiogram sign Fig. 5 on page 36 Fig. 8 on page 39 CT angiogram sign consists of enhancing branching pulmonary vessels in a 5 homogeneous low attenuating consolidation of lung parenchyma. The sign can be 6 observed in pulmonary consolidation of varying etiologies. Page 8 of 60

9 Fig. 5: Mucinous adenocarcinoma. Contrast-enhanced CT scan reveals CT angiogram sign. References: radiology, nagasaki university hospital - Nagasaki/JP Page 9 of 60

10 Fig. 6: Invasive mucinous adenocarcinoma. Pathological microphotograh in low magnification view shows patent pulmonary arteries (arrow) inside the lesion. References: radiology, nagasaki university hospital - Nagasaki/JP Page 10 of 60

11 Fig. 7: Invasive mucinous adenocarcinoma. Pathological microphotograh in higher magnification view shows alveolar space filled with atypical goblet cells and mucus. References: radiology, nagasaki university hospital - Nagasaki/JP Page 11 of 60

12 Fig. 8: MALT lymphoma. Contrast-enhanced CT scan reveals CT angiogram sign. References: radiology, nagasaki university hospital - Nagasaki/JP CT halo sign Fig. 9 on page 40 Fig. 10 on page 41 Fig. 12 on page 43 CT halo sign is characterized by ground glass opacity surrounding a pulmonary nodule 7 or mass. This finding was first described in patients with angioinvasive aspergillosis ; however, it can be seen in many other pathological conditions such as infection, 8 neoplastic and inflammatory diseases. Page 12 of 60

13 Fig. 9: Angioinvasive aspergillosis. TSCT shows ill-defined ground-glass opacity surrounding the pulmonary nodules. References: radiology, nagasaki university hospital - Nagasaki/JP Page 13 of 60

14 Fig. 10: Adenocarcinoma. TSCT shows zone of intermediate attenuation surrounding the nodule. References: radiology, nagasaki university hospital - Nagasaki/JP Page 14 of 60

15 Fig. 11: Adenocarcinoma. Pathological microphotograh in low magnification view shows fibrotic scarring at the center (arrows) and lepidic growth pattern (arrow heads) at the periphery. References: radiology, nagasaki university hospital - Nagasaki/JP Page 15 of 60

16 Fig. 12: MALT lymphoma. TSCT shows ill-defined ground-glass opacity surrounding the pulmonary nodule. References: radiology, nagasaki university hospital - Nagasaki/JP 8 Differential Diagnosis of CT halo sign Infection Fungal infection (aspergillosis,mucormycosis, etc) Septic embolism Mycobacterial infection Viral infection(herpes simplex, varicella zoster, cytomegalovirus, etc) Page 16 of 60

17 Neoplasm Primary tumor (adenocarcinoma, Kaposi sarcoma, squamous cell carcinoma) Metastasis (angiosarcoma,choriocarcinoma, osteosarcoma,etc) Miscellaneous GPA (granulomatosis with polyangitis) Eosinophic lung disease Organizing pneumonia Pulmonary endometriosis Reversed halo sign Fig. 13 on page 44 A reversed halo sign represents a nodule, which has central ground-glass opacity surrounded by consolidation. This sign has been described as a finding in organizing pneumonia and other infectious or inflammatory etiologies. The nodules with this pattern 9 are typically multiple. Page 17 of 60

18 Fig. 13: Cryptogenic organizing pneumonia. TSCT shows a ring of consolidation surrounding central ground-glass opacity. References: radiology, nagasaki university hospital - Nagasaki/JP Signs of marginal characteristics spicula notch pleural indentation pit-fall sign Spicula Fig. 14 on page 45 Fig. 16 on page 47 Page 18 of 60

19 Spicula in nodular lesions are defined as linear strands extending from the margin of 10 nodules into the lung parenchyma but not extending to the pleura. Spicula is one of the chracteristic findings in malignant nodules. This finding, however, can also be seen in benign nodules in the presence of 11 emphysema. Spicula, therefore, cannot be used to reliably discriminate between malignant and benign nodules associated with severe emphysema. Fig. 14: Adenocarcinoma. TSCT shows a pulmonary nodule with irregular margin and spicula. Page 19 of 60

20 References: radiology, nagasaki university hospital - Nagasaki/JP Fig. 15: Adenocarcinoma. Pathological microphotograph shows irregular margin of the tumor with a spicula (arrow). References: radiology, nagasaki university hospital - Nagasaki/JP Page 20 of 60

21 Fig. 16: Inflammatory nodule. TSCT shows a pulmonary nodule associated with pulmonary emphysema. The nodule shows irregular margin with spiculas simulating a malignant lesion. This nodule disappeared one month later. References: radiology, nagasaki university hospital - Nagasaki/JP Notch Fig. 17 on page 48 Fig. 18 on page 49 Notch or lobulation is defined as an abrupt bulging of the lesion contour. Malignant 10 nodules generally have irregular spiculated margin with notch or lobulation. The Rigler notch sign refers to an indentation in the border of a solid lung mass at a feeding vessel, thus suggesting bronchial carcinoma. However, this sign is also observed in other Page 21 of 60

22 conditions including granulomatous infections, and its value in differential diagnosis is therefore limited. Notch can also be seen at the portion in contact with vessels in rapidly growing tumors, such as peripheral squamous or large cell carcinoma. Fig. 17: Squamous cell carcinoma. TSCT shows a lobulated nodule. References: radiology, nagasaki university hospital - Nagasaki/JP Page 22 of 60

23 Fig. 18: Vessels are seen at the notch of the tumor margin (arrow) in contrastenhanced CT. References: radiology, nagasaki university hospital - Nagasaki/JP Page 23 of 60

24 Fig. 19: Pathological microphotograph in low magnification view shows the vessels (arrows) at edge of the squamous cell carcinoma. References: radiology, nagasaki university hospital - Nagasaki/JP Pleural indentation Fig. 20 on page 51 Pleural indentation (or pleural tag) consists of a linear opacity that extends from a peripheral nodule or mass to the visceral pleura. It can represent a strand of fibrous tissue that extends from the nodule to the visceral pleura or can result from inward retraction 10 and apposition of a thickened visceral pleura. Although they are associated most commonly with adenocarcinoma, they may be seen with other histologic subtypes; they also may be identified in pulmonary metastases and 12 granulomas. Page 24 of 60

25 Fig. 20: Adenocarcinoma. TSCT shows a pulmonary nodule with irregular margin, spicula and pleural indentation. References: radiology, nagasaki university hospital - Nagasaki/JP Pit-fall sign Fig. 21 on page 52 Page 25 of 60

26 Pit-fall signs refer to multiple linear strands between the nodule and chest wall and/ or interlobar fissure. Adjacent normal lung expands to fill the dead space between the retracted visceral pleura that corresponds to multiple indentations on CT. The pit-fall sign on preoperative CT suggests a possible pleural involvement correlated 13,14 with a poor prognosis. Fig. 21: Adenocarcinoma. TSCT shows a pulmonary nodule present far from chest wall. Adjacent normal lung expands to fill the dead space between the retracted visceral pleura that corresponds to multiple indentations on CT. References: radiology, nagasaki university hospital - Nagasaki/JP Page 26 of 60

27 Fig. 22: Pathological microphotograph in low magnification shows the adenocarcinoma beneath the pleura. The pleura is invaginated into the lung. References: radiology, nagasaki university hospital - Nagasaki/JP Various CT signs Page 27 of 60

28 Adenocarcinoma Sq. ca. FOP Hamartoma MALT ± (mucinous) air + bronchogram CT angiogram sign CT halo sign +(lepidic growth) reversed halo sign ±(lepidic growth) spicula + ± + ± ± notch ± + ± + - pleural indentation + ± ± pit-fall sign + ± Sq. ca.; squamous cell carcinoma FOP; focal organizing pneumonia Signs of specific lesions air crescent sign comet tail sign feeding vessel sign sarcoid galaxy sign Air-crescent sign Fig. 23 on page 54 "Air-crescent sign" refers to the crescent of air seen in invasive aspergillosis, semi15 invasive aspergillosis or other processes with necrosis. However, the air around the fungus ball is also crescent shaped and the term "air-crescent 16 sign" is often used in that instance. Page 28 of 60

29 Fig. 23: Pulmonary aspergillosis. TSCT shows a mass with "air-crescent sign" in the right middle lobe. References: radiology, nagasaki university hospital - Nagasaki/JP Comet tail sign Fig. 24 on page 55 Rounded atelectasis is an unusual type of lung atelectasis where there is infolding of redundant pleura. It is a radiological diagnosis and must be differentiated from other mass-like lesions in the basal part of the lung, including malignant pleural and pulmonary tumors. Specific radiological features such as irregular pleural thickening and the "comet17 tail" sign help to make the correct diagnosis and to avoid unnecessary surgery. Page 29 of 60

30 Fig. 24: Rounded atelectasis. A "comet tail sign" is produced by the distortion of vessels and bronchi that lead to an adjacent area of rounded atelectasis on chest CT. References: radiology, nagasaki university hospital - Nagasaki/JP Feeding vessel sign Fig. 25 on page 56 Feeding vessel sign consists of a distinct vessel leading directly to a nodule or a mass. This sign indicates either that the lesion has a hematogenous origin or that the disease 18 process occurs near small pulmonary vessels. A number of hematogenous non-neoplastic disorders of the lung can show this sign, for example: Pulmonary vasculitis Pulmonary infarction Septic embolism Angioinvasive pulmonary aspergillosis Page 30 of 60

31 Fig. 25: GPA (Granulomatosis with polyangitis). TSCT shows a cavitating nodule with distinct central vessel leading into it. References: radiology, nagasaki university hospital - Nagasaki/JP Sarcoid galaxy sign Fig. 26 on page 57 Parenchymal nodules in pulmonary sarcoidosis shows a characteristic pattern 19 resembling a galaxy, which corresponded to coalescent granulomas. This appearance is thought to result from aggregation of large numbers of interstitial granulomas rather than representing a true alveolar process. Some authors have therefore applied a more appropriate term "pseudoalveolar sarcoidosis". Page 31 of 60

32 Fig. 26: Pulmonary sarcoidosis. TSCT shows "sarcoid galaxies" that are composed of numerous small granulomas. References: radiology, nagasaki university hospital - Nagasaki/JP Images for this section: Page 32 of 60

33 Fig. 1: Pneumonia. Chest radiograph shows consolidation with air bronchogram. Page 33 of 60

34 Fig. 2: Adenocarcinoma. Thin-section CT (TSCT) shows an "air bronchogram" running into the lesion. Page 34 of 60

35 Fig. 3: Adenocarcinoma. Pathological microphotograh in low magnification view shows dilated bronchiole (arrow) entering into the tumor. Page 35 of 60

36 Fig. 4: MALT lymphoma. TSCT shows an "air bronchogram" in the lesion. Page 36 of 60

37 Fig. 5: Mucinous adenocarcinoma. Contrast-enhanced CT scan reveals CT angiogram sign. Page 37 of 60

38 Fig. 6: Invasive mucinous adenocarcinoma. Pathological microphotograh in low magnification view shows patent pulmonary arteries (arrow) inside the lesion. Page 38 of 60

39 Fig. 7: Invasive mucinous adenocarcinoma. Pathological microphotograh in higher magnification view shows alveolar space filled with atypical goblet cells and mucus. Page 39 of 60

40 Fig. 8: MALT lymphoma. Contrast-enhanced CT scan reveals CT angiogram sign. Page 40 of 60

41 Fig. 9: Angioinvasive aspergillosis. TSCT shows ill-defined ground-glass opacity surrounding the pulmonary nodules. Page 41 of 60

42 Fig. 10: Adenocarcinoma. TSCT shows zone of intermediate attenuation surrounding the nodule. Page 42 of 60

43 Fig. 11: Adenocarcinoma. Pathological microphotograh in low magnification view shows fibrotic scarring at the center (arrows) and lepidic growth pattern (arrow heads) at the periphery. Page 43 of 60

44 Fig. 12: MALT lymphoma. TSCT shows ill-defined ground-glass opacity surrounding the pulmonary nodule. Page 44 of 60

45 Fig. 13: Cryptogenic organizing pneumonia. TSCT shows a ring of consolidation surrounding central ground-glass opacity. Page 45 of 60

46 Fig. 14: Adenocarcinoma. TSCT shows a pulmonary nodule with irregular margin and spicula. Page 46 of 60

47 Fig. 15: Adenocarcinoma. Pathological microphotograph shows irregular margin of the tumor with a spicula (arrow). Page 47 of 60

48 Fig. 16: Inflammatory nodule. TSCT shows a pulmonary nodule associated with pulmonary emphysema. The nodule shows irregular margin with spiculas simulating a malignant lesion. This nodule disappeared one month later. Page 48 of 60

49 Fig. 17: Squamous cell carcinoma. TSCT shows a lobulated nodule. Page 49 of 60

50 Fig. 18: Vessels are seen at the notch of the tumor margin (arrow) in contrast-enhanced CT. Page 50 of 60

51 Fig. 19: Pathological microphotograph in low magnification view shows the vessels (arrows) at edge of the squamous cell carcinoma. Page 51 of 60

52 Fig. 20: Adenocarcinoma. TSCT shows a pulmonary nodule with irregular margin, spicula and pleural indentation. Page 52 of 60

53 Fig. 21: Adenocarcinoma. TSCT shows a pulmonary nodule present far from chest wall. Adjacent normal lung expands to fill the dead space between the retracted visceral pleura that corresponds to multiple indentations on CT. Page 53 of 60

54 Fig. 22: Pathological microphotograph in low magnification shows the adenocarcinoma beneath the pleura. The pleura is invaginated into the lung. Page 54 of 60

55 Fig. 23: Pulmonary aspergillosis. TSCT shows a mass with "air-crescent sign" in the right middle lobe. Page 55 of 60

56 Fig. 24: Rounded atelectasis. A "comet tail sign" is produced by the distortion of vessels and bronchi that lead to an adjacent area of rounded atelectasis on chest CT. Page 56 of 60

57 Fig. 25: GPA (Granulomatosis with polyangitis). TSCT shows a cavitating nodule with distinct central vessel leading into it. Page 57 of 60

58 Fig. 26: Pulmonary sarcoidosis. TSCT shows "sarcoid galaxies" that are composed of numerous small granulomas. Page 58 of 60

59 Conclusion Understanding of the CT signs is important for the diagnosis and management of clinical cases. We should recognize the original meaning of these signs, correlation to the pathological findings and their limitations. Personal information References Fleischner FG. The visible bronchial tree; A roentogen sign in pneumonic and other pulmonary consolidations. Radiology 50; , 1948 Kuriyama K et al. Prevalence of air brohchograms in small peripheral carcinomas of the lung on thin-section CT: comparison with benign tumors. AJR 156: , 1991 Honda T et al. Radiographic and pathological analysis of small lung adenocarcinoma using the new IASLC classification. Clin Radiol 68: e21-6, 2013 Zhao F et al. CT features of focal organizing pneumonia: An analysis of consecutivehistopathologically confirmed 45 cases. EJR 83:73-8, 2014 Im JG et al: Lobar bronchioloalveolar carcinoma: "angiogram sign" on CT scans. Radiology 176: Murayama S et al. "CT angiogram sign"in obstructive pneumonitis and pneumonia. J Comput Assist Tomogr 17: , 1993 Kuhlman JE et al. Invasive pulmonary aspergillosis in acute leukemia: characteristic findings on CT, the CT halo sign, and the role of CT in early diagnosis. Radiology 157: , 1985 Lee YR et al: CT halo sign: the spectrum of pulmonary disease. BJR 78: , 2005 Kim SJ et al. Reversed halo sign on highresolution CT of cryptogenic organizing pneumonia: diagnostic implications. AJR 180: ,2003 Zwirewich CV et al. Solitary pulmonary nodule: high-resolution CT and radiologic-pathologic correlation. Radiology 179: , 1991 Matsuoka S et al. Peripheral solitary pulmonary nodule: CT findings in patients with pulmonary emphysema. Radiology 235: , 2005 Dong MX et al. Limited value of shape, margin and CT density in the discrimination between benign and malignant screen detected solid pulmonary nodules of the NELSON trial Morimoto K, et al: A pitfall of CT findings in peripheral lung adenocarcinoma. JCAT 26: , 2002 Page 59 of 60

60 14. Li M, et al: Pit-fall sign on computed tomography predicts pleural involvement and poor prognosis in non-small cell lung cancer. Lung cancer. 46: , Slevin ML et al. The air crescent sign of invasive pulmonary aspergillosis in acute leukemia. Thorax 37: , Rosberts CM et al. Intrathoracic aspergilloma: role of CT in diagnosis and treatment. Radiology 165: 123-8, Verschakelen JA et al. Rounded atelectasis of the lung: diagnosis on conventional radiography and CT. EJR 6:305-8, Kuhlman JE et al: Wegener granulomatosis; CT features of parenchymal lung disease. JCAT 15: , Nakatsu M, et al: Large coalescent parenchymal nodules in pulmonary sarcoidosis: "sarcoid galaxy" sign. AJR 178: , 2002 Page 60 of 60