Ann Thorac Surg 2004;77:1094-1096
© 2004 The Society of Thoracic Surgeons
Case report
Pseudo tumors of the lung after lung volume reduction surgery
Inger F. Oey, FRCSa,
Kanagaratnam Jeyapalan, FRCRb,
James J. Entwisle, FRCRb,
David A. Waller, FRCS CTh*a
a Department of Thoracic Surgery Leicester, United Kingdom
b Department of Radiology, Glenfield Hospital, Leicester, United Kingdom
Accepted for publication April 28, 2003.
* Address reprint requests to Dr Waller, Glenfield Hospital, Leicester LE3 9QP, UK
e-mail: ingeroey{at}hotmail.com
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Abstract
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We describe 2 patients who underwent lung volume reduction surgery, who postoperatively had computed tomographic scans that showed symptomatic mass lesions suggestive of malignancy and an inhaled foreign body. Investigations excluded these conditions with the remaining likely diagnosis of pseudotumor secondary to buttressing material. These potential sequelae of lung volume reduction surgery should be recognized in follow-up investigations.
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Introduction
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Lung volume reduction surgery (LVRS) is an operation performed in many centers, which aims to improve the health status of patients with severe emphysema. Postoperative computed tomographic (CT) scans have been performed for diagnostic as well as research purposes [1]. However, we would like to present 2 patients who had CT scans performed after LVRS, which led to misleading findings and perhaps unnecessary procedures.
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Case reports
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Patient 1
The first patient is a 55-year-old man who underwent unilateral video-assisted thoracoscopic LVRS. The lung was resected using the EZ45 stapling gun (Ethicon Endo-Surgery, Cincinnati, OH). The staple lines were buttressed using dry bovine pericardial strips (Peri Strips, Bio-Vascular, St. Paul, MN). His postoperative recovery was uneventful. Histology of the resected lung specimen confirmed emphysema. In addition, a fibrous nodule was found containing necrotic material surrounded by a wall of histiocytes and lymphocytes. In the center, numerous Aspergillus hyphae were seen.
He was readmitted 1 month postoperatively with a history of increasing shortness of breath and pleuritic chest pain. A chest roentgenogram showed middle lobe collapse (Fig 1). To exclude pulmonary embolism, a CT angiogram was performed, which revealed a mass in the middle lobe with the appearance of a circular foreign body of approximately 2 cm in diameter centered within the mass (Fig 2). However a rigid bronchoscopy failed to show any abnormality.

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Fig 1. Chest roentgenogram after lung volume reduction surgery showing a mass in the lower zone of the right lung.
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He was treated with a course of antibiotics after which he made a full clinical recovery. A repeat CT scan was performed 12 months after his original operation, which showed a reduction in the extent of the mass and surrounding consolidation. These findings would make a diagnosis of lung cancer unlikely.
Patient 2
The second patient is a 66-year-old who underwent unilateral video-assisted thoracoscopic LVRS, using the Versafire-GIA (Autosuture, Norwalk, CT) and endo-GIA60 stapling gun (Auto Suture) with Peri Strips (Bio-Vascular) to buttress the stapling lines. During routine follow-up after 3 months as an outpatient, a chest roentgenogram was performed in which a right upper lobe mass was found (Fig 3). A subsequent CT scan confirmed a mass suspicious of malignancy with mediastinal lymphadenopathy. We proceeded to cervical mediastinoscopy with right paratracheal lymph node biopsy. Histology of this showed reactive hyperplasia only. We then proceeded to a CT-guided biopsy, but again histology did not show any malignancy. Subsequent chest roentgenograms as much as 2 years postoperatively showed that the mass had reduced in size.

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Fig 3. Chest roentgenogram after lung volume reduction surgery showing a mass in the upper zone of the right lung.
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Comment
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It has been found that the results after LVRS are better in patients with heterogeneous emphysema. CT scans have been used in the selection of these patients. However, we also perform CT scans in all patients referred for LVRS to exclude other conditions such as malignancies. After LVRS, all our patients are seen in the outpatient clinic for routine follow-up. In addition, some patients are readmitted as an in-patient either with a surgical complication or with an exacerbation of their chronic obstructive pulmonary disease. In a number of these patients a postoperative CT scan is performed for diagnostic purposes.
It has been shown that a mass shadow on chest roentgenogram and CT scan in the lung can be caused by a reaction to foreign bodies such as nonabsorbable sutures (eg, braided silk, braided polyester) [2, 3]. In these reported cases, patients had developed hemoptysis and proceeded to have surgery.
We have previously reported 3 patients who coughed up staples after LVRS [4]. This was thought to be due to a reaction to the bovine pericardial strips. It seems that this inflammatory reaction can also cause a mass lesion, although the histology in the second case did not specifically show foreign body inflammatory changes.
Surgical metal clips are known to cause artifacts on CT scans with streaks radiating from the clips. Titanium has been found to cause less artifact compared with stainless steel or tantalum [5]. In the first presented case, the suspected foreign body was reported to be 2 cm in diameter, and a rigid bronchoscopy was performed to exclude an intrabronchial foreign body. Perhaps the density was caused by a row of clips organized in a circle due to the surface of the lung being folded together.
It could be that the suspected foreign body was in fact calcification in an inflammatory mass. Glutaraldehyde used in the pretreatment of bovine pericardium is known to cause calcification. However, the first CT scan to show this mass was performed within 1 month postoperatively. As previously mentioned, the histology of the first case revealed an aspergilloma. Perhaps the mass found postoperatively is related to the presence of an aspergilloma, even though a preoperative CT scan did not show an abnormal mass.
However, these patients, who have smoking related emphysema, are at risk of developing a malignant tumor. Hazelrigg and colleagues [6] found a 6.4% overall incidence of malignancy in a group of 281 patients undergoing LVRS. Therefore, a mass lesion appearing after LVRS should be further investigated.
In conclusion, after LVRS, mass lesions may develop, which are pseudotumors related to the foreign material left on the lung surface. Nevertheless, these lesions do need to be investigated to exclude more serious conditions.
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References
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- Lando Y., Boiselle P., Shade D., Travaline J.M., Furukawa S., Criner G.J. Effect of lung volume reduction surgery on bony thorax configuration in severe COPD. Chest 1999;116:30-39.[Medline]
- Baba K., Nagao K., Matsuda M., et al. An operative case of suture-granuloma which resulted from an intra-pulmonary treatment 10 years ago and manifested hemoptysis. Kyobu Geka 1996;49:1048-1051.[Medline]
- Nonaka M., Arai T., Inagaki K., Morita T., Yano M., Miyazawa H. Intra-pulmonary suture abscess with hemoptysis after partial resectionconcerning to the pathogenesis of the suture abscess. Nippon Kyobu Geka Gakkai Zasshi 1991;39:2088-2091.[Medline]
- Oey I., Waller D.A. Metalloptysis: a late complication of lung volume reduction surgery. Ann Thorac Surg 2001;71:1694-1695.[Abstract/Free Full Text]
- Silverman P.M., Spicer L.D., McKinney R., Jr, Feldman D.B. Computed tomographic evaluation of surgical clip artifact: tissue phantom and experimental animal assessment. Comput Radiol 1986;10:37-40.[Medline]
- Hazelrigg S.R., Boley T.M., Weber D., Magee M.J., Naunheim K.S. Incidence of lung nodules found in patients undergoing lung volume reduction. Ann Thor Surg 1997;64:303-306.[Abstract/Free Full Text]
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