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CHEST RADIOLOGY Table of Contents   
Year : 2007  |  Volume : 17  |  Issue : 3  |  Page : 181-185
Pictorial essay: Atypical pulmonary metastases: Radiologic appearances

Uludag University, Faculty of Medicine, Department of Radiology, Bursa, Turkey

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How to cite this article:
Topal NB, Oruc E, Gokalp G, Topal U. Pictorial essay: Atypical pulmonary metastases: Radiologic appearances. Indian J Radiol Imaging 2007;17:181-5

How to cite this URL:
Topal NB, Oruc E, Gokalp G, Topal U. Pictorial essay: Atypical pulmonary metastases: Radiologic appearances. Indian J Radiol Imaging [serial online] 2007 [cited 2021 Feb 28];17:181-5. Available from:
The lungs are among the most common sites of metastases from non-pulmonary malignancies, since the lungs function as the primary capillary filter of venous drainage for most organs. [1] The overall incidence, in those who die from malignancy, ranges from 20%-54%. [1],[2] Metastases are usually scattered in the lung parenchyma or pleura and often infiltrate adjacent structures. [1],[2],[3],[4],[5],[6],[7] The most common primary sites are breast, colon, kidney, uterus, head and neck. [1],[2],[3],[4],[5]

Pulmonary metastases present a wide spectrum of radiologic findings. [3] Typical findings include peripherally located, multiple, round, variable-sized nodules (hematogenous spread) and diffuse thickening of interstitium (lymphangitic spread). [2],[3],[4] Although various diseases can present as multiple pulmonary nodules, metastatic disease accounts for a high percentage. Gross et al reported that 73% of cases with pulmonary nodules resulted from metastatic diseases. [8]

Sometimes, metastatic disease in adults, presents with unusual radiologic appearances, making it more difficult to distinguish these lesions from nonmalignant pulmonary diseases. This pictorial essay covers the radiologic appearances of atypical forms of pulmonary metastases.

   Cavitation Top

Although cavitation in pulmonary metastases is not as frequent as in primary tumors, metastases should always be considered in the differential diagnosis of multiple cavitary lesions. [9],[10] The percentage of cavitation in pulmonary metastases is approximately 4% in contrast to 9% in primary cancers. [2],[3]

Squamous cell carcinomas are the most common type of cavitating metastases, associated with a 70% rate of cavitation. [2],[3],[9] The head and neck and urogenital system are the most common primary organ sites [Figure - 1],[Figure - 2]. [2],[3],[11] Chemotherapy is also known to induce cavitation. [3] Several mechanisms for cavitation of nodules are postulated. Tumor necrosis and a check-valve mechanism developing by means of tumor infiltration into air-containing structures are some of them. [2],[3]

Metastatic sarcomas can also cavitate and result in pneumothorax. [12] They may present as multiple cystic lesions [Figure - 3]. [10],[12],[13],[14] They resemble bullae and may have extremely thin walls. [10] Bullae-like lesions on CT, in patients with a known sarcoma, should be interpreted with particular caution. [12]

   Calcification Top

Generally calcification of a pulmonary nodule is suggestive of benignity, as seen in a granuloma or hamartoma. [2],[3] Metastases from synovial sarcoma, giant cell tumor of the bone and colon, ovary, breast and thyroid carcinomas may calcify. [2],[3],[15],[16],[17],[18],[19],[20],[21]

Multi-focal calcifications are unusual in metastatic disease, except for those from osteosarcoma and chondrosarcoma [Figure - 4]. [3],[15],[17],[18] Dystrophic calcification can also occur after treatment of nodular metastases. [3] Bone formation may develop in osteosarcoma and synovial sarcoma. [15],[17],[18] CT cannot differentiate calcification or ossification in metastatic nodules from those seen in granulomas or hamartomas but multiple calcified nodules may be a sign of metastases, [2] in the correct clinical setting.

   Hemorrhage Top

Hemorrhage in metastatic lesions can be depicted on CT images. Fragility of neovascular tissue leading to rupture of the vessels is considered the cause of hemorrhage. [2],[3] Peripheral hemorrhage causes surrounding ground-glass attenuation, termed the CT "halo sign" [Figure - 5]. [2],[3],[22] Angiosarcomas and choriocarcinomas are the most common causes of hemorrhagic metastases. [2],[3],[13],[22],[23] Ground-glass opacity however, is not a specific finding and is also seen in invasive aspergillosis [24],[25] as well as in candidiasis, Wegener's granulomatosis, tuberculomas associated with hemoptysis, focal scar, atypical adenomatous hyperplasia, bronchoalveolar carcinoma and lymphoma. [2],[3],[23],[26]

Endobronchial metastases

Endobronchial metastases (EBM) from extrathoracic tumors are rarely seen. [2],[3],[6],[7] The frequency of EBM varies from 2% to 28%. [1],[7] There are two mechanism causing EBM. The first is direct invasion of the bronchial wall by means of aspiration of the tumor cells, lymphatic spread or hematogenous metastasis to the bronchial wall. The second is when tumor cells in lymph nodes or lung parenchyma surrounding the bronchus grow along the bronchial tree and some portion of the lesion invades the bronchial wall. [2] Differentiation of EBM from primary lung cancer can be difficult without knowledge of the patient's history. [1],[27]

Radiologic findings in EBM are similar to those seen in primary endobronchial lung cancer. A mass in the bronchus and mucus plugging at the periphery are commonly seen [Figure - 6],[Figure - 7], though often the findings are atypical . Patients with EBM may also have parenchymal lesions and the diagnosis is often confirmed only after transthoracic biopsy, fine-needle aspiration or open-lung biopsy. [1],[28] In the majority of cases, the definitive diagnosis is made by the presence of a primary malignancy at another site, whose histologic appearance is similar to that of the endobronchial lesion. [6],[7]

The most common primary sites causing EBM are breast, kidney and colon. [7],[29] It is necessary to be aware of this phenomenon, since the treatment differs from that of primary lung cancer.

   Solitary Metastases Top

When a solitary pulmonary nodule is detected in a patient with an extrathoracic malignancy, the probability of metastasis is approximately 25%. [30] Using CT, 46% of solitary pulmonary nodules detected in patients with extrathoracic malignancies were proven to be metastases after resection by video assisted thoracoscopic surgery. [31] The most frequent malignancies include melanoma, sarcomas and carcinomas of colon, breast, kidney, bladder and testis [Figure - 8]. [2],[3],[4],[32],[33] Quint et al reported that patients with a solitary pulmonary nodule and a history of head and neck cancer were much more likely to have a primary bronchogenic carcinoma than a lung metastasis. If the primary site is colon, kidney or uterus, the chance of the nodule being a primary lung cancer is higher. But if the extrathoracic primary cancer is melanoma, sarcoma or testicular cancer, the solitary lesion is more likely be a metastasis rather than a primary lung cancer. [34]

   Conclusion Top

Radiologists should be aware of the spectrum of radiologic appearances in atypical pulmonary metastases as described above.

   References Top

1.Froudarakis ME, Bouros D, Siafakas NM. Endoluminal metastases of the tracheobronchial tree: Is there any way out? Chest 2001;119:679-81.  Back to cited text no. 1  [PUBMED]  [FULLTEXT]
2.Seo FB, Im JG, Goo JM, Chung MJ, Kim MY. Atypical pulmonary metastases: Spectrum of radiologic findings. Radiographics 2001;21:403-17.   Back to cited text no. 2    
3.Hirakata K, Nakata H, Nakagawa T. CT of pulmonary metastases with pathological correlation. Semin Ultrasound CT MR 1995;16:379-94.  Back to cited text no. 3  [PUBMED]  
4.Hirakata K, Nakata H, Haratake J. Appearance of pulmonary metastases on high-resolution CT scans: Comparison with histopathologic findings from autopsy specimens. AJR Am J Roentgenol 1993;161:37-43.   Back to cited text no. 4  [PUBMED]  
5.Murata K, Takahashi M, Masayuki M, Kawaguchi N, Furukawa A, Ohnaka Y, et al. Pulmonary metastatic nodules: CT-pathologic correlation. Radiology 1992;182:331-5.   Back to cited text no. 5    
6.Sorensen JB. Endobronchial metastases from extrapulmonary solid tumors. Acta Oncol 2004;43:73-9.  Back to cited text no. 6    
7.Akoglu S, Uηan ES, Çelik G, Şener G, Sevinη C, Kılınη O, et al. Endobronchial metastases from extrathoracic malignancies. Clin Exp Metastasis 2005;22:587-91.  Back to cited text no. 7    
8.Gross BH, Glazer GM, Bookstein FL. Multiple pulmonary nodules detected by computed tomography: Diagnostic implications. J Comput Assist Tomogr 1985;9:880-5.  Back to cited text no. 8  [PUBMED]  
9.Wolpowitz A. Cavitation of pulmonary metastases. S Afr Med J 1971;49:157.  Back to cited text no. 9    
10.Traweek T, Rotter AJ, Swartz W, Azumi N. Cystic pulmonary metastatic sarcoma. Cancer 1990;65:1805-11.  Back to cited text no. 10  [PUBMED]  
11.Angulo JC, Lopez JI, Flores N. Cavitation of lung metastases from bladder cancer. Report of two cases. Tumori 1993;79:141-3.  Back to cited text no. 11    
12.Chan DP, Griffith JF, Lee TW, Chow LT, Yim AP. Cystic pulmonary metastases from epithelioid cell sarcoma. Ann Thorac Surg 2003;75:1652-4.  Back to cited text no. 12  [PUBMED]  
13.Itoh T, Mochizuki M, Kumazaki S, Ishihara T, Fukayama M. Cystic pulmonary metastases of endometrial stromal sarcoma of the uterus, mimicking lymphangiomyomatosis: A case report with immunohistochemistry of HMB45. Pathol Int 1997;47:725-9.  Back to cited text no. 13  [PUBMED]  
14.Songur N, Karakas A, Arikan M, Demir S, Bozkurt A, Ucaner A. Multiple cystic pulmonary metastases from osteosarcoma. Respiration 2005;72:418.  Back to cited text no. 14    
15.Tubbs WS, Brown LR, Beabout JW, Rock MG, Unni KK. Benign giant-cell tumor of bone with pulmonary metastases: Clinical findings and radiologic appearance of metastases in 13 cases. AJR Am J Roentgenol 1992;158:331-4.   Back to cited text no. 15  [PUBMED]  
16.Jimenez JM, Casey SO, Citron M, Khan A. Calcified pulmonary metastases from medullary carcinoma of the thyroid. Comput Med Imaging Graph 1995;19:325-8.  Back to cited text no. 16  [PUBMED]  [FULLTEXT]
17.Maxwell JR, Yao L, Eckardt JJ, Doberneck SA. Case report: Densely calcifying synovial sarcoma of the hip metastatic to the lungs. Skeletal Radiol 1994;23:673-5.  Back to cited text no. 17  [PUBMED]  
18.deSantos LA, Lindell MM Jr, Goldman AM, Luna MA, Murray JA. Calcification within metastatic pulmonary nodules from synovial sarcoma. Orthopedics 1978;1:141-4   Back to cited text no. 18  [PUBMED]  
19.Kavanagh E, Gleeson T, Hargaden G, Fenlon H. Metastatic colorectal carcinoma: An unusual cause of calcified pulmonary metastases. AJR Am J Roentgenol 2004;183:1841-3.  Back to cited text no. 19  [PUBMED]  [FULLTEXT]
20.Samuels T, Kerenyi N, Hamilton P. Cystosarcoma phylloides: Calcified pulmonary metastases detected by computed tomography. Can Assoc Radiol J 1990;41:217-8.  Back to cited text no. 20  [PUBMED]  
21.Kim SJ, Choi JA, Lee SH, Choi JY, Hong SH, Chung HW, Kang HS. Imaging findings of extrapulmonary metastases of osteosarcoma. Clin Imaging 2004;28:291-300.  Back to cited text no. 21  [PUBMED]  [FULLTEXT]
22.Tateishi U, Hasegawa T, Kusumoto M, Yamazaki N, Iinuma G, Muramatsu Y, et al. Metastatic angiosarcoma of the lung: spectrum of CT findings. AJR Am J Roentgenol 2003;180:1671-4.  Back to cited text no. 22  [PUBMED]  [FULLTEXT]
23.Ohtsuka T, Watanabe K, Kaji M, Naruke T, Suemasu K. A clinicopathological study of resected pulmonary nodules with focal pure ground-glass opacity.Eur J Cardiothorac Surg 2006;30:160-3.  Back to cited text no. 23  [PUBMED]  [FULLTEXT]
24.Gaeta M, Blandino A, Scribano E, Minutoli F, Volta S, Pandolfo I. Computed tomography halo sign in pulmonary nodules: Frequency and diagnostic value. J Thorac Imaging 1999;14:109-13.  Back to cited text no. 24  [PUBMED]  
25.Greene RE, Schlamm HT, Oestmann JW, Stark P, Durand C, Lortholary O, et al. Imaging findings in acute invasive pulmonary aspergillosis: clinical significance of the halo sign. Clin Infect Dis 2007;44:373-9.  Back to cited text no. 25  [PUBMED]  [FULLTEXT]
26.Greene RE, Schlamm HT, Oestmann JW, Stark P, Durand C, Lortholary O, et al. Imaging findings in acute invasive pulmonary aspergillosis: clinical significance of the halo sign. Clin Infect Dis 2007;44:373-9.  Back to cited text no. 26  [PUBMED]  [FULLTEXT]
27.Salud A, Porcel JM, Rovirosa A, Bellmunt J. Endobronchial metastatic disease: Analysis of 32 cases. J Surg Oncol 1996;62:249-52.  Back to cited text no. 27  [PUBMED]  
28.Ikezoe J, Johkoh T, Takeuchi N, Ishida T, Morimoto S, Kitamura I, et al. CT findings of endobronchial metastasis. Acta Radiol 1991;32:455-60.  Back to cited text no. 28  [PUBMED]  
29.Katsimbri PP, Bamias AT, Froudarakis ME, Peponis IA, Constantopoulos SH, Pavlidis NA. Endobronchial metastases secondary to solid tumors: report of eight cases and review of the literature. Lung Cancer 2000;28:163-70.  Back to cited text no. 29  [PUBMED]  [FULLTEXT]
30.Cahan WG, Shah JP, Castro EB. Benign solitary lung lesions in patients with cancer. Ann Surg 1977;187:241-4.  Back to cited text no. 30    
31.Ginsberg MS, Griff SK, Go BD, Yoo HH, Schwartz LH, Panicek DM. Pulmonary nodules resected at video-assisted thoracoscopic surgery: Etiology in 426 patients. Radiology 1999;213:277-82.  Back to cited text no. 31  [PUBMED]  [FULLTEXT]
32.Tatsuta M, Shiozaki K, Masutani S, Hashimoto K, Imamura H, Ikeda M, et al. Splenic and pulmonary metastases from renal cell carcinoma: Report of a case. Surg Today 2001;31:463-5.  Back to cited text no. 32  [PUBMED]  [FULLTEXT]
33.Bouros D, Papadakis K, Siafakas N, Fuller AF Jr. Patterns of pulmonary metastasis from uterine cancer. Oncology 1996;53:360-3.  Back to cited text no. 33  [PUBMED]  
34.Quint LE, Park CH, Iannettoni MD. Solitary pulmonary nodules in patients with extrapulmonary neoplasms. Radiology 2000;217:257-61.  Back to cited text no. 34  [PUBMED]  [FULLTEXT]

Correspondence Address:
Naile Bolca Topal
Uludag University, Faculty of Medicine, Department of Radiology, 16059, Bursa
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-3026.34723

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  [Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7], [Figure - 8]

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