Ann Thorac Surg 2004;77:2203-2204
© 2004 The Society of Thoracic Surgeons
Case report
Extralobar pulmonary sequestration simulates posterior neurogenic tumor
Ryszard W. Lupinski, MD, PhDa*,
Thirugnanam Agasthian, MMed, FRCSa,
Chong Hee Lim, FRCS, FAMSa,
Yeow Leng Chua, MMed, FRCSa
a Department of Cardiothoracic Surgery, National Heart Centre, Singapore
Accepted for publication June 13, 2003.
* Address reprint requests to Dr Lupinski, Department of Cardiothoracic Surgery, National Heart Centre, Mistri Wing, 17 Hospital Ave, Singapore 168752
e-mail: rilup2{at}singnet.com.sg
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Abstract
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We report a case of 19-year-old asymptomatic man with posterior mediastinal mass thought to be of neurogenic origin on computed tomography scan. During video-assisted thoracic surgery the mass appeared to be an extralobar pulmonary sequestration. Surgery was straightforward by division of vascular pedicle. Histopathology confirmed diagnosis.
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Introduction
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Pulmonary sequestration is defined as a mass of nonfunctional pulmonary tissue that lacks a normal communication with tracheobronchial tree. The arterial supply derives directly from the aorta or intercostals arteries. Two types of pulmonary sequestration have been identified: intralobar, which is contained within the visceral pleura; and extralobar, which has own sac and is separated from the rest of the lung. This case is an example of extralobar pulmonary sequestration.
A 19-year-old asymptomatic man was noted to have an opacity on chest roentgenogram during routine examination. Computed tomography scan of the thorax (Fig 1)
revealed a posterior triangular-shaped mediastinal mass. A diagnosis of posterior mediastinal mass of neurogenic origin was made. Magnetic resonance imaging revealed similar findings (Fig 2).
The patient was admitted to the hospital for elective video-assisted thoracic surgery (VATS) excision of the tumor. During surgery the mass appeared to be an extralobar sequestration (Fig 3).
A pyramid-shaped, well-encapsulated mass (Fig 4)
was lying freely on the posterior aspect of the chest in the right paravertebral gutter. Vascular pedicle was arising from the aorta and azygos vein.
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Fig 3. View during video-assisted thoracic surgery of extralobar sequestration: apparent intercostal vessels (IC) at the base of vascular pedicle (VP). (ELS = extralobar sequestration, RLL = collapsed right lower lobe.)
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Histopathology examination confirmed a diagnosis of pulmonary sequestration. Sections of the mass showed lung parenchymal tissue comprising dilated duct-like bronchioles and alveoli. Focally, they formed cysts of bronchogenic origin filled with a large amount of inspissated mucin.
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Comment
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First described by Rektorzik in 1861, pulmonary sequestration is defined as a mass of nonfunctional pulmonary tissue that lacks a normal communication with the tracheobronchial tree [1]. The etiology of the defect is thought to be congenital.
There are two types of pulmonary sequestration: intralobar (ILS), contained within the visceral pleura; and extralobar (ELS), which has own pleural sac and is separated from the rest of the lung. Intralobar sequestration is six times more common than ELS [2]. Extralobar sequestration occurs on the left in more than 90% of the cases [3]. Complications are uncommon in ELS. Because the accessory lung tissue is sequestered within its own pleura, infection is unusual with ELS. The arterial supply derives directly from the aorta or intercostals arteries. The venous drainage typically is through systemic veins (azygos, intercostals veins).
Useful diagnostic tools in ELS are computed tomography scanning, magnetic resonance imaging, magnetic resonance angiography, or angiography [1, 3, 4]. Angiography appears to be the gold standard, confirms diagnosis, and defines vascular anatomy. Pulmonary sequestration needs to be differentiated from scimitar syndrome, horseshoe lung, cystic adenoid malformation, pulmonary arteriovenous fistula, and, as presented in our case, neurogenic mediastinal mass. Surgery for ELS is straightforward and can be done by VATS. An alternate treatment modality, embolization of the feeding systemic artery, can be considered in selected cases [5].
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References
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- Felker R.E., Tonkin I.L.D. Imaging of pulmonary sequestration. AJR 1990;154:241-249.[Free Full Text]
- Sugio K., Kaneko S., Yokoyama H., Ishida T., Sugimachi K., Hasuo K. Pulmonary sequestration in older child and in adults. Int Surg 1992;77:102-107.[Medline]
- Lin C.H., Lin C.T., Chen C.Y., Peng H.C., Chen H.C., Wang P.Y. Pulmonary sequestration. Chin Med J (Taipei) 1994;53:168-172.
- Naidich D.P., Rumanck W.M., Ettenger N.A., et al. Congenital anomalies of the lung in adults: MR diagnosis. AJR 1988;151:13-19.[Abstract/Free Full Text]
- Curros F., Chigot V., Emond S., et al. Role of embolisation in the treatment of bronchopulmonary sequestration. Pediatr Radiol 2000;30:769-773.[Medline]
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Abstract
Introduction
