Case Report
Chest Imaging
October 2007

Unilateral Usual Interstitial Pneumonia Associated with Sarcoma of the Pulmonary Artery

The histologic pattern of usual interstitial pneumonia is heterogeneous areas of interstitial inflammation, dense acellular collagen deposition, fibroblastic foci, and honeycombing [1]. Various clinical conditions have been known to be associated with usual interstitial pneumonia, including idiopathic pulmonary fibrosis, collagen vascular disease, drug toxicity, chronic hypersensitivity pneumonitis, asbestosis, and infection with agents such as Epstein–Barr virus and HIV-1 [24]. To our knowledge, however, an association between usual interstitial pneumonia and chronic pulmonary ischemia has not been reported in the English literature. We present a case of unilateral usual interstitial pneumonia associated with slowly growing pulmonary artery sarcoma and suggest that chronic pulmonary ischemia may be one of the etiologic factors in usual interstitial pneumonia.

Case Report

A 52-year-old man with dyspnea was admitted to our institution. The medical history revealed that he had been admitted to a local hospital 5 years previously because of the incidental finding of a pulmonary mass on a chest radiograph obtained for a routine medical examination. Contrast-enhanced chest CT pursuant to the chest radiograph showed a 5.5 × 2.5 cm intraluminal filling defect in the right main pulmonary artery, raising the possibility of pulmonary artery sarcoma (Fig. 1A). No other abnormality was present in the underlying lung parenchyma (Fig. 1B). Excisional biopsy of the intravascular mass was recommended, but the patient declined because he had no specific symptoms and feared major surgery.
Five years after the evaluation at the local hospital, the patient had gradually increasing dyspnea and was admitted to our institution for further evaluation. Contrast-enhanced chest CT showed the previously detected intravascular mass in the right main pulmonary artery had increased in extent, measuring 8.5 × 3 cm in maximum diameter and extended to the lobar branches of the pulmonary artery (Fig. 1C). The presence of several tortuous hypertrophied intercostal arteries newly identified in the right hemithorax and hypertrophy of the right bronchial artery suggested a systemic arterial supply to the ipsilateral right lung in association with chronic pulmonary ischemia (Fig. 1C). On lung window high-resolution CT scans (1-mm collimation), the ipsilateral right lung exhibited subpleural areas of ground-glass attenuation and irregular linear opacities with honeycombing, findings suggestive of usual interstitial pneumonia (Fig. 1D).
To confirm the diagnosis and for treatment, open thoracotomy and excisional biopsy were performed. At surgery, frozen biopsy specimens obtained from the right main pulmonary artery contained pulmonary artery sarcoma. The patient underwent curative right pneumonectomy and reconstruction of the main pulmonary artery with a bovine pericardial patch. Multiple collateral vessels were identified along the costal pleura. Gross examination revealed a pale yellowish partly myxoid intravascular mass in the lumen of the right main pulmonary artery (Fig. 1E). The tumor exhibited mainly intravascular polypoid growth with focal invasion of the adjacent lung parenchyma. Histopathologic examination of the intravascular mass revealed low-grade pulmonary artery sarcoma consisting of atypical spindle cells in myxoid stroma, moderate cellular pleomorphism, and rare mitoses. The biopsy specimens obtained from the subpleural lung parenchyma of the right middle and lower lobes contained areas of microscopic honeycombing and irregular interstitial fibrosis, findings consistent with usual interstitial pneumonia (Fig. 1F). The patient recovered uneventfully and had no evidence of local recurrence or distant metastasis 2 months after surgery.
Fig. 1A 52-year-old man with unilateral usual interstitial pneumonia associated with pulmonary artery sarcoma. Initial contrast-enhanced chest CT scan obtained with mediastinal window at local hospital shows intraluminal filling defect (arrows) in right main pulmonary artery.
Fig. 1B 52-year-old man with unilateral usual interstitial pneumonia associated with pulmonary artery sarcoma. Initial contrast-enhanced chest CT scan obtained with lung window at level of inferior pulmonary vein shows no abnormal findings in underlying lungs.
Fig. 1C 52-year-old man with unilateral usual interstitial pneumonia associated with pulmonary artery sarcoma. Contrast-enhanced chest CT scan obtained with mediastinal window at our institution 5 years after A and B shows intravascular mass (straight arrows) in right main pulmonary artery has grown and extends to lobar pulmonary arteries. New appearance of hypertrophied right bronchial artery (curved arrow) and intercostal arteries (arrowheads) suggests presence of collateral vessels for systemic arterial supply to chronically ischemic lung.
Fig. 1D 52-year-old man with unilateral usual interstitial pneumonia associated with pulmonary artery sarcoma. High-resolution (1-mm collimation) CT scan obtained with lung window at level of inferior pulmonary vein shows subpleural areas of ground-glass attenuation and irregular linear opacities with honeycombing (arrowheads) in right middle and lower lobes. Findings suggest usual interstitial pneumonia involving only ipsilateral right lung.
Fig. 1E 52-year-old man with unilateral usual interstitial pneumonia associated with pulmonary artery sarcoma. Photograph of pneumonectomy specimen shows pale yellowish myxoid intravascular mass in right main pulmonary artery and extending to lobar pulmonary arteries (arrows). Area of subpleural fibrosis and honeycombing is evident in right lower lobe (star).
Fig. 1F 52-year-old man with unilateral usual interstitial pneumonia associated with pulmonary artery sarcoma. Photomicrograph of biopsy specimen obtained from subpleural area of right lower lobe shows areas of microscopic honeycombing (arrows) and irregular interstitial fibrosis (star). Findings are consistent with usual interstitial pneumonia. (H and E, ×40)

Discussion

The systemic arterial supply to the lungs can be congenital or acquired [5]. Hypertrophy of normal systemic arteries, which include the bronchial arteries, intercostal arteries, internal mammary arteries, inferior phrenic arteries, and branches of the thyrocervical trunk, has been known to develop in patients with bronchiectasis, pulmonary tuberculosis, chronic pulmonary thromboembolism, or chronic obstructive pulmonary disease [5]. These systemic arteries supply the lungs by means of intrapulmonary bronchopulmonary arterial anastomoses or transpleural systemic–pulmonary artery anastomoses [5].
In patients with chronic pulmonary thromboembolism, the reduction in pulmonary arterial pressure due to pulmonary artery occlusion is known to result in tortuous dilatation of bronchial arteries, which serve as collateral vessels supplying the ischemic lung [5]. The systemic–pulmonary arterial communication also has been found in association with chronic pulmonary artery occlusion induced by Takayasu's arteritis [6]. In our case, we believe that a very slowly growing low-grade pulmonary artery sarcoma had been causing longstanding pulmonary ischemia due to pulmonary arterial occlusion, which led to secondary hypertrophic changes in bronchial and intercostal arteries, making them collateral vessels for systemic arterial supply to the ischemic lung.
Usual interstitial pneumonia is a relatively nonspecific pattern of chronic lung injury characterized by fibrosis and honeycomb remodeling [7]. Although various clinical conditions, including collagen vascular disease, drug toxicity, chronic hypersensitivity pneumonitis, asbestosis, and viral infection, have been known to be associated with usual interstitial pneumonia [24], the association with chronic pulmonary ischemia has not been not reported, to our knowledge. In our case, we believe that unilateral usual interstitial pneumonia might have been derived from 5 years of chronic ischemic lung injury induced by slowly growing pulmonary artery sarcoma. The presence of a chronic ischemic lung injury can be supported by compensatory hypertrophic changes in the ipsilateral bronchial and intercostal arteries, which served as collateral vessels for the ischemic lung. An alternative explanation for the unilateral pulmonary fibrosis is the possibility of the presence of a fibrogenetic factor secreted from the sarcoma, localizing with more concentration in the ipsilateral lung, and resulting in pulmonary fibrosis. The findings in our case of unilateral usual interstitial pneumonia associated with slowly growing pulmonary artery sarcoma suggest that chronic pulmonary ischemia may be an etiologic factor in usual interstitial pneumonia.

Footnotes

Address correspondence to T. S. Kim.
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References

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Katzenstein AL, Myers JL. Idiopathic pulmonary fibrosis: clinical relevance of pathologic classification. Am J Respir Crit Care Med 1998; 157:1301 –1315
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American Thoracic Society/European Respiratory Society. American Thoracic Society/European Respiratory Society International Multidisciplinary Consensus Classification of the Idiopathic Interstitial Pneumonias. Am J Respir Crit Care Med 2002; 165:277–304
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Pfleger A, Eber E, Popper H, Zach MS. Chronic interstitial lung disease due to Epstein-Barr virus infection in two infants. Eur Respir J 2000; 15:803 –806
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Semenzato G, Agostini C. HIV-related interstitial lung disease. Curr Opin Pulm Med 1995; 1:383–391
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Do KH, Goo JM, Im JG, Kim KW, Chung JW, Park JH. Systemic arterial supply to the lungs in adults: spiral CT findings. RadioGraphics 2001; 21:387–402
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Ishikawa T. Systemic artery-pulmonary artery communication in Takayasu's arteritis. AJR 1977; 128:389–393
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Fukuoka J, Leslie KO. Chronic diffuse lung disease. In: Leslie KO, Wick MR, eds. Practical pulmonary pathology. Philadelphia, PA: Churchill Livingstone, 2005:181 –258

Information & Authors

Information

Published In

American Journal of Roentgenology
Pages: W221 - W223
PubMed: 17885035

History

Submitted: June 13, 2005
Accepted: September 4, 2005

Keywords

  1. cardiovascular disease
  2. CT
  3. embolism
  4. ischemia
  5. lung disease

Authors

Affiliations

Semin Chong
Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-dong, Gangnam-gu, Seoul 135-710, South Korea.
Tae Sung Kim
Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50, Ilwon-dong, Gangnam-gu, Seoul 135-710, South Korea.
Man Pyo Chung
Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Eun Yoon Cho
Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.
Jhingook Kim
Department of Thoracic and Cardiovascular Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea.

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