Eur J Cardiothorac Surg 2002;21:943-945
© 2002 Elsevier Science NL
Primary leiomyosarcoma of the anterior mediastinum
Atilla Ero
lua*,
Can Kürkçüolua,
Nurettin Karaolanolua,
Nesrin Gürsanb
a Department Of Thoracic Surgery, Medical Faculty, Atatürk University, 25240 Erzurum, Turkey
b Department of Pathology, Medical Faculty, Atatürk University, 25240 Erzurum, Turkey
Received 22 November 2001;
received in revised form 1 February 2002;
accepted 6 February 2002.
* Corresponding author. Tel.: +90-442-316-6333x2182; fax: +90-442-316-6340
e-mail: atilaeroglu{at}hotmail.com
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Abstract
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Primary mediastinal leiomyosarcoma are extremely rare tumors, which develop from smooth muscle, usually in the esophagus or main vessels. Very few cases have been reported in the literature and only two of these developed from small vessels in the soft tissue of the anterior mediastinum. We report on a 45-year-old man who presented with a huge anterior mediastinal tumor. The tumor was surgically removed with right thoracotomy and the diagnosis of well-differentiated leiomyosarcoma was established. It probably originated from the anterior mediastinal tissue, so at operation a continuity was not found between the tumor and neighboring structures. This rare and interesting histopathology is discussed and the literature is reviewed.
Key Words: Leiomyosarcoma • Mediastinum • Mesenchymal tumor
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1. Introduction
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Soft tissue sarcomas comprise 0.7% of adult malignancies [1]; the most frequent site is the uterus. Other locations are the intestinum, the retroperitoneum, and the vascular system. These tumors constitute approximately 2% of all tumors that occur in the mediastinum [2]. Mediastinal leiomyosarcomas are rare neoplasms that account for about 1.4% of all soft tissue sarcomas and for approximately 11% of primary mediastinal sarcomas [3]. Anterior mediastinal, low-grade leiomyosarcomas, pedunculated from the soft tissue, are extremely rare.
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2. Case report
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A 41-year-old man was admitted to our hospital with a chief complaint of dyspnea and chest pain. On admission, physical examination revealed decreased breath sounds in his right chest. Cardiac examination was negative for murmurs and extra heart sounds. Heart rate was 116 beats/min, blood pressure was 100/70 mmHg, and temperature was 37.1 °C. Laboratory studies revealed a hemoglobin level of 13.8 g/dl and a platelet count of 460 000/ml. A chest radiograph showed a right mediastinal mass. A computed tomography (CT) scan of the thorax showed a 10x8x7-cm right anterior mediastinal soft tissue mass surrounding the vena cava with calcification and right pleural effusion (Fig. 1) . Cytological examination of the pleural effusion was reported as nonspecific fluid. The result of the needle aspiration of the mass was diagnosed as mesenchymal tumor. We detected no metastatic lesion on thorax CT and abdomen ultrasound.
The tumor was approached through a right anterolateral thoracotomy; a hard, well-circumscribed mass, filled the whole anterior mediastinum. There was no contact to the vascular tissue. There was a heterogeneous mass with cystic and nodular areas. There was a sub-complete atelectatic upper lobe of the right lung but no infiltration of the lung parenchyma. The tumor was completely resected with mediastinal pleura. There were no enlarged thoracic and mediastinal lymph nodes.
The resected tumor was 11x9x7 cm in diameter, white, firm, nodular, myxoid and well circumscribed. Histopathologic examination showed a low-grade leiomyosarcoma that was well differentiated, and originated in the mediastinal soft tissue. The tumor was composed of spindle cells with eosinophilic cytoplasm and fusiform nuclei organized into bundles. Pleomorphic and giant cells and 2–3 mitoses per high-power field were also present (Fig. 2)
. Immunocytochemical results showed strong diffuse staining for smooth muscle actin and patchy, strong staining for KiM1P. Surgery sites were reported as negative for malignancy at histopathologic examination.
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Fig. 2. Histopathologic appearances of the tumor, showing bundles of smooth muscle fibers containing uniform spindle-shaped nuclei (H&E, x100).
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In the postoperative period, the patient recovered completely and was discharged 9 days after operation. Postoperative radiotherapy was done. At the 8-month follow-up, the patient was clinically well.
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3. Discussion
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Leiomyosarcomas of the mediastinum are rare. Only six cases had been reported until 1993 [4–7]. All six were in the visceral compartment, and no definitive site of origin could be identified in any of these tumors. Moran and colleagues [8] reported ten cases of leiomyosarcoma in the mediastinum in 1994. At surgery none of these lesions arose from either the aorta or the esophagus. Only in three of patients were anterior mediastinal lesions found. Gomez-Roman and Val-Bernal [9] reported the case of a 76-year-old man with a tumor in the anterior superior mediastinum that was composed of both liposarcoma and leiomyosarcoma.
The origin of these tumors within the mediastinum remains a subject of speculation. Their origin in the mediastinum has been related either to the smooth muscles of the esophagus, the mediastinal veins, or to a teratogenic development, despite the lack of other types of tissue. It is possible that such lesions may arise from small vessels within mediastinal soft tissue. Leiomyosarcomas arising within the soft tissues of the mediastinum unassociated with neighboring structures are extremely rare and only four cases have been reported previously [8]. Two of these were located in the anterior superior mediastinum [8]. This case is the third patient reported with leiomyosarcoma of the anterior mediastinum that originated in the mediastinal soft tissue. In our case a continuity was not found between the tumor and neighboring structures at operation, which suggests that the tumor originated in the small vessels within mediastinal soft tissue.
Leiomyosarcomas may attain big sizes and exhibit various kinds of clinical symptoms according to their localization. Histological typing is very important in determining the type and extent of therapy. Surgical excision of the tumor is the therapy of choice in all cases. Surgical approach depends on the localization and the size of the tumor. If the lesion is located at the anterior mediastinum and cannot be resected by thoracotomy, sternotomy is the choice of surgical approach. In our case we performed thoracotomy due to localization of the tumor at the right mediastinum; if the differentiation of the lesion with lung is imperceptible a lung resection may be necessary.
There is no consensus with regard to radiotherapy and chemotherapy, but the general consensus on this subject is that the complete resection of these tumors is an important prognostic factor [3,10]. Radiotherapy may be of value for the palliation of unresectable cases but the role of additional radio-and chemotherapy remains questionable. In the study of Auliac et al. [10], the use of chemotherapy was mentioned especially in the metastatic dissemination but the results remained uncertain in their study. Burt et al. [3] reported that radiation therapy and chemotherapy, age and size did not affect survival.
In summary, although rare, leiomyosarcoma should be included in the differential diagnosis of anterior mediastinal lesions.
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References
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Abstract
1. Introduction
