Ann Thorac Surg 2000;70:957-958
© 2000 The Society of Thoracic Surgeons
Case report
Mediastinal dumbbell angiolipoma
Giampiero Negri, MDa,
Paolo Regolo, MDb,
Simonetta Gerevini, MDc,
Gianluigi Arrigoni, MDd,
Piero Zannini, MDa
a Department of Thoracic Surgery, San Raffaele Hospital, Milan, Italy
b Department of Neurosurgery, San Raffaele Hospital, Milan, Italy
c Department of Neuroradiology, San Raffaele Hospital, Milan, Italy
d Department of Pathology, San Raffaele Hospital, Milan, Italy
Address reprint requests to Dr Negri, Via Gaetano Donizetti 1, 20122 Milan, Italy
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Abstract
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Nonneurogenic dumbbell tumors are rare. This report describes the case of a 46-year-old woman with a symptomatic mediastinal dumbbell angiolipoma. The tumor was successfully resected using a single-stage procedure, combining a posterior microneurosurgical and thoracoscopic approach. The patient made an uneventful recovery and the neurologic symptoms improved immediately.
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Introduction
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Tumors with a paravertebral portion and a spinal canal portion connected by a foraminal segment are commonly called dumbbell tumors because of their typical shape. These tumors may arise from the paravertebral sulci, the intervertebral foramen, or the spinal canal space, and they may occur in the cervical region, thoracic region, and lumbosacral regions [1]. Most dumbbell tumors are neurogenic in origin [1]. Spinal angiolipomas are uncommon [2], and reports of an angiolipoma occurring within the posterior mediastinum are rare [3]. We describe a case of a dumbbell mediastinal angiolipoma successfully treated by a combined microneurosurgical and thoracoscopic approach.
A 46-year-old woman was admitted to our hospital with a 3-month history of a mild Brown-Sequard syndrome.
Computed tomography of the chest demonstrated a mediastinal tumor (3.5 x 4.7 cm) with regular margins and apparently encapsulated. The tumor extended into the spinal canal through the left enlarged intervertebral foramen of T5–6. On magnetic resonance imaging, the lesion showed a dishomogeneous low signal intensity on T1-weighted images and a slightly bright signal on T2-weighted images. The canal spinal component of the lesion compressed the thecal sac to the right. After gadolinium injection there was a homogeneous intense enhancement of the lesion (Fig 1).
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Fig 1. Axial T1-weighted image after gadolinium injection: dumbbell tumor enlarging the left intervertebral foramen of T5–6. Both the intravertebral component (a) and the extravertebral component (b) of the lesion are enhanced strongly. The lesion displaces the cord laterally (curved arrow).
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The preoperative diagnosis was a benign neurogenic dumbbell tumor, and the patient was considered a candidate for a combined microneurosurgical and thoracoscopic approach. Initially, the patient was positioned prone; a left T5–6 laminectomy and a wide foramenotomy were carried out. The tumor was firmly adherent to the nerve root but did not seem to originate from it. The nerve root was therefore transected. This allowed removal of the anterior epidural portion of the lesion without exerting undue traction on the cord. Frozen section examination of the lesion demonstrated a benign mesenchymal lipomatoid tumor with a proliferation of numerous vascular channels. The patient was then positioned as for a full left posterolateral thoracotomy. Thoracoscopic removal was performed through four ports. The parietal pleura was incised around the tumor, and careful dissection was carried out in the extrapleural tissue. Once the tumor was mobilized, it was placed in an endobag and retrieved through one of the port sites (ENDOPATH, Ethicon, Endo-Surgery, Cincinnati, OH). The postoperative period was uneventful and the neurologic symptoms improved immediately. Pathologic examination confirmed an angiolipoma (Fig 2). The patient was discharged from hospital 7 days after her operation and remained asymptomatic within a 2-year follow-up period.
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Fig 2. Photomicrograph (phosphotungstic acid hematoxylin stain; magnification, 100x) of the resected tumor specimen showing a mixture of mature fat cells and small vascular channels with multiple microthrombi.
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Comment
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Angiolipomas are rare, benign encapsulated tumors and occur mainly in young adults. They consist of a mixture of mature fat cells and narrow vascular channels. Characteristically, the vascular formations contain multiple fibrin microthrombi (Fig 2), a feature that distinguishes angiolipomas from ordinary lipomas [4]. Although angiolipomas are typically located in the subcutis of the forearms [4], uncommon locations have been reported in the literature, such as the epidural spine [2] and the posterior mediastinum [3].
In our case, the angiolipoma was a true dumbbell tumor of the mediastinum. The larger component of the tumor lay in the left posterior mediastinum, and the spinal canal portion of the lesion caused cord compression and neurologic symptoms.
Surgical treatment is considered the primary treatment for dumbbell tumors, and a variety of surgical approaches to mediastinal neurogenic dumbbell tumors have been described [5]. The single-stage procedure, combining a posterior microneurosurgical and thoracoscopic approach, was recently proposed [6] for the removal of benign lesions. In the last three years we have used this approach in two other patients with mediastinal dumbbell tumors, both benign and neurogenic in origin. We consider this combined approach indicated in patients in whom a large component of the tumor lies in the mediastinum and who have real canal spinal tumor involvement. If the principal tumor is located in the mediastinum and the extension is limited to the foramen, the tumor may be resected by foramenotomy using the thoracoscopic approach without laminectomy. The posterior approach alone, which allows both laminectomy and costotransversectomy, appears to be preferable when the principal bulk of the tumor is intraspinal and the intrathoracic portion is small [5].
In conclusion, the combined microneurosurgical and thoracoscopic approach is a safe and effective means of removing benign mediastinal dumbbell tumors, whether neurogenic or nonneurogenic in origin.
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References
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Isoda H., Takahashi M., Mochizuki T., et al. MRI of dumbbell-shaped spinal tumors. J Comput Assist Tomogr 1996;20:573-582.[Medline]
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Provenzale J.M., McLendon R.E. Spinal angiolipomas. Am J Neuroradiol 1996;17:713-719.[Abstract]
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Kline M.E., Patel B.U., Agosti S.J. Noninfiltrating angiolipoma of the mediastinum. Radiology 1990;175:737-738.[Abstract/Free Full Text]
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Ensinger F.M., Weiss S.W. Benign lipomatous tumors. In: Ensinger F.M., Weiss S.W., eds. Soft tissue tumors. St. Louis: Mosby, 1995:381-430.
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Grillo H.C., Ojemann R.G. Mediastinal and intraspinal "dumbbell" neurogenic tumors. In: Martini N., Vogt-Moykopf I., eds. . International trends in general thoracic surgery. St. Louis: Mosby, 1989:205-210.
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Vallières E., Findlay J.M., Fraser R.E. Combined microneurosurgical and thoracoscopic removal of neurogenic dumbbell tumors. Ann Thorac Surg 1995;59:469-472.[Abstract/Free Full Text]
Accepted for publication December 26, 1999.
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Abstract
Introduction
