gms | German Medical Science

GMS Thoracic Surgical Science

Deutsche Gesellschaft für Thoraxchirurgie (DGT)

ISSN 1862-4006

Benign mesenchymoma of the mediastinum: a report and review of the literature

Benignes Mesenchymom des Mediastinums: Fallbeschreibung und Literaturrecherche

Case Report

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  • corresponding author Joel T.K. Melton - Department of Thoracic Surgery, Southampton General Hospital, Southampton, UK
  • David F. Weeden - Department of Thoracic Surgery, Southampton General Hospital, Southampton, UK

GMS Thorac Surg Sci 2006;3:Doc02

The electronic version of this article is the complete one and can be found online at:

Published: August 30, 2006

© 2006 Melton et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.


Benign mesenchymoma is a rare type of germ cell tumour. An extensive literature search revealed only one described case of mediastinal mesenchymoma in Europe and three cases in Asia. We describe our recent experience of a mediastinal mesenchymoma and present the fascinating imaging and operative findings.

The preoperative diagnosis of these lesions remains difficult and therefore surgical resection is recommended.


Das benigne Mesenchymom des Mediastinums ist ein seltener Tumor der germinalen Zelllinie. Bisher wurden weltweit nur vier Fälle beschrieben, ein Fall in Europa und drei in Asien.

Die Autoren präsentieren ihre Erfahrung in der Behandlung dieser seltenen Mediastinalerkrankung. Die präoperative Diagnose dieses Tumors ist schwierig, eine operative Entfernung wird empfohlen.

Case report

A 57 year old man was found to have a large radio-opacity on chest x-ray (Figure 1 [Fig. 1]) whilst undergoing investigation for renal calculi. He was experiencing some mild excertional dyspnoea but was otherwise asymptomatic. The patient underwent bronchoscopic examination which revealed subtle extrinsic compression of the left main bronchus. Contrast CT scan (Figure 2 [Fig. 2]) demonstrated a large calcified mediastinal mass compressing the left main bronchus and left upper lobe pulmonary arteries. He underwent thoracotomy and left upper lobectomy to excise the mass. Histopathological diagnosis was of benign mesenchymoma (hamartoma). The lesion measured 12 x 12cm, was roughly spherical and consisted of firm, grey, glassy tissue. Microscopically it contained mature cartilage, cellular fibrous tissue, collections of fat cells and muscle. There were also areas of focal ossification with haemopoesis. The patient recovered well from surgery, was discharged from hospital 6 days later and was well (without dyspnoea) at last follow up.

Literature review

Benign mesenchymoma is a rare type of germ cell tumour which histologically contains two or more differentiated mesenchymal elements not usually found within the same tumour [1]. It can be referred to as a type of hamartoma (a benign tumor-like malformation resulting from faulty development in an organ and composed of an abnormal mixture of tissue elements that develop and grow at the same rate as normal elements).

Descriptions in the medical literature are uncommon and rarely occur in the mediastinum. These tumours most frequently occur in the renal and peri-renal regions although cases have been described affecting the oral cavity, the chest wall and breast and the gastrointestinal tract [1], [2], [3], [4].

Mediastinal mesenchymomal tumours are extremely rare and presentation to the thoracic surgeon may be incidental but symptoms can result from compression of local structures [5], [2], [6]. A literature search revealed only one case of mediastinal mesenchymoma described in Europe and 3 cases described in Asia [2], [5], [6], [7]. The size of the lesion we report is the largest described in the literature. Benign mesenchymoma may cause local complications through compression of surrounding structures with growth. Despite the benign nature of these tumours, malignant transformation can occur and has been described [8]. Little is known about the stage at which this transformation occurs or the stimulus for malignant change. The principle for treatment is to undertake diagnostic tests as applicable to the tumour site and arrange both local and systemic staging if malignant transformation is suspected. If biopsy cannot be safely undertaken (as in this report), surgical excision is required. Chemotherapy and radiotherapy have been shown to have a limited role and prognosis is poor with high rates of local and systemic reccurrence [9].


This lesion had unusual appearances both on plain x-ray and CT scan and the operative findings and histological diagnosis were both unusual and informative. Preoperative diagnosis of benign mesenchymoma may be difficult and surgical resection will be curative. Although rare, this case illustrates the need to consider the more uncommon benign and malignant neoplasms in the differential diagnosis of unusual appearances on chest x-ray.


Klouda MJ, Yaremko LM, Howeedy AA, et al. Giant benign mesenchymoma of the breast. Surgery. 1991;109(4):539-42.
Boke E, Sarigul A, Sungur A, et al. Benign mesenchymoma of the oesophagus. Eur J Cardiothorac Surg. 1997;11(1):196-8.
Psaila J, Carachi R, Raine PA, et al. Thoracic mesenchymoma of infancy. J Pediatr Surg. 1996;31(5):726-8.
Friedman M, Chow J, Toriumi DM, et al. Benign neoplasms of the oral cavity. Clin Plast Surg. 1987;14(2):223-31.
Uramoto H, Oyama T, Yoshimatsu T, et al. Benign mesenchymoma of the mediastinum. Jpn J Thorac Cardiovasc Surg. 2000;48(12):814-6.
Ohara T, Fukushima K, Hasegawa T, et al. Giant benign mesenchymoma of the mediastinum causing superior vena cava syndrome: report of a case. Surg Today. 1993;23(10):917-9.
Hsieh SP, Tseng HH. Benign mesenchymoma of the mediastinum: a case report. Zhonghua Yi Xue Za Zhi (Taipei). 1996;58(3):213-7.
Hedlund GL, Bisset GS, Bove KE. Malignant neoplasms arising in cystic hamartomas of the lung in childhood. Radiology. 1989;173(1):77-9.
Deslee G, Guillou PJ, Baehrel B, Lebargy F. Malignant mesenchymoma of the pleura. Interactive Cardiovascular and Cardiothoracic Surgery. 2003;2:376-8.