|Year : 2013 | Volume
| Issue : 4 | Page : 721-723
Inflammatory myofibroblastic tumor occurs in the mediastinum
Xiangjiao Meng, Renben Wang
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, No. 440 Jiyan Road, Jinan, Shandong, China
|Date of Web Publication||11-Feb-2014|
Department of Radiation Oncology, Shandong Cancer Hospital and Institute, No. 440 Jiyan Road, Jinan, Shandong 250117
Source of Support: None, Conflict of Interest: None
Inflammatory myofibroblastic tumor (IMT) is a rare disease. We report a rare case of inflammatory myofibroblastic tumor occurs in the mediastinum. Chest contrast-enhanced computed tomography (CT) showed a heterogeneously enhanced irregular mass in the anterior mediastinum; a small pericardial effusion was also noted. The diagnosis was confirmed by histopathology and immunohistochemical study.
Keywords: Inflammatory myofibroblastic tumor, mediastinum, thoracoscopic surgery
|How to cite this article:|
Meng X, Wang R. Inflammatory myofibroblastic tumor occurs in the mediastinum. J Can Res Ther 2013;9:721-3
| > Introduction|| |
Inflammatory myofibroblastic tumor (IMT) is a rare disease. The most frequent site of IMT is in the lung, while it occurs rarely in the mediastinum. We report an IMT in the mediastinum, which showed a heterogeneously enhanced irregular mass in the anterior mediastinum and a small pericardial effusion on computed tomography (CT). The mass was resected under a thoracoscopic surgery.
| > Case Report|| |
A 34-year-old woman presented with a 1-year history of discomfort behind the sternum and hypodynamia of limbs. On admission, chest contrast-enhanced computed tomography (CT) showed a heterogeneously enhanced irregular mass in the anterior mediastinum; a small pericardial effusion was also noted [Figure 1]a-c.
|Figure 1: Chest contrast-enhanced computed tomography (CT) image. (a-c) A heterogeneously enhanced irregular mass in the anterior mediastinum before operation; there is a small pericardial infiltration. (d) The image after thoracoscopic surgery, the tumor was not completely resected. (e) After radiation therapy, the volume of the tumor was little smaller than the preradiation volume. (f) The volume of the tumor became much smaller, and it nearly disappeared after 2 years|
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The patient underwent a thoracoscopic surgery. During the operation it was found that the tumor located in anterior mediastinum, in front of the pulmonary artery, invaded the diaphragmatic nerve and pericardium. The tumor was not completely resected. The resected tumor was 3.5 × 3.0 × 3.0 cm in size. Microscopic examination revealed a mixture of spindle cells and inflammatory cells including lymphocytes, plasma cells, immunoblasts, histiocytes, and fibrous tissue [Figure 2]a. Immunohistochemical study demonstrated spindle cells positive for vimentin [Figure 2]b and smooth muscle actin [Figure 2]c and negative for S-100 and epithelial membrane antigen( EMA). The tumor had a low Ki-67 proliferation. As the tumor was not completely resected [Figure 1]d and a redo excision was not allowed for heart disease, the patient underwent radiation therapy with a prescribed fraction dose of 2 Gy and total dose of 50 Gy. After radiation therapy, the volume of the tumor was smaller than the preradiation volume [Figure 1]e. It has been 2 years since the last fraction of radiation. The volume of the tumor became much smaller, and it nearly disappeared [Figure 1]f. Now the patient is in good condition without discomfort behind the sternum and hypodynamia of limbs.
|Figure 2: (a) Hematoxylin-eosin staining: The tumor is made up of a proliferation of spindle-shaped cells in a background of inflammatory cells (×200). (b) Immunohistochemical study: Spindle-shaped cells positive for vimentin (×200). (c) Immunohistochemical study: Spindle-shaped cells positive for smooth muscle actin (×200)|
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| > Discussion|| |
The pathogenesis of IMT was thought to be an exaggerated immunologic response by proliferated spindle cells and primary myofibroblasts to injury, inflammation, or infection; so, the IMT was initially reported as "inflammatory pseudotumor." , But it is now viewed as a true neoplasm because it can invade adjacent structures, as in our patient, and even may have distant metastasis. ,
There are no specific signs, radiologic manifestations, or symptoms related to IMT. It is impossible to make an accurate diagnosis just on the basis of the clinical presentation and its diversified radiologic manifestations. It is difficult to distinguish IMT from malignant tumors on the basis of small tissue samples obtained from needle biopsy. In most cases, an accurate diagnosis is made based on the histopathologic and immunohistochemical study from a resected tumor.  Hematoxylin-eosin staining of the resected specimen showed the proliferation of spindle-shaped cells in a background of inflammatory cells. Immunohistochemical study is helpful in diagnosing and distinguishes IMT from other types of tumors, which usually show positive staining for smooth muscle actin and vimentin, as in our patient.
Owing to the rarity of IMT, it is hard to gather evidence on effective treatment. Anti-inflammatory therapy, chemotherapy, and radiation therapy have all been tried. , IMT usually requires surgical resection for both proper diagnosis and adequate treatment. Complete resection and achieving negative margins leads to excellent outcome.  In this case, the volume of the tumor became much smaller, and it nearly disappeared due to the delayed effect of radiation therapy. So, radiation therapy was recommended, with a prescribed fraction dose of 2 Gy and total dose of 50 Gy if the tumor was not completely resected.
| > References|| |
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