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Expression of transforming growth factor β in idiopathic fibrosing mediastinitis
ARTICLE IN PRESS Respiratory Medicine Extra (2005) 1, 71–74
respiratory MEDICINE Extra
CASE REPORT
Expression of transforming growth factor b in idiopathic fibrosing mediastinitis Osamu Ishimotoa,, Nobuyuki Satob, Tadashi Imaib, Mitsuomi Kaimoric, Akio Ebinab a
Department of Respiratory Medicine, Sendai Kosei Hospital, 4-15 Hirosemachi, Aobaku, Sendai, Miyagi 980-0873, Japan b Department of Respiratory Medicine, Aomori Prefectural Central Hospital, 2-1-1 Higashi-tsukurimichi, Aomori 030-8553, Japan c Department of Pathology, Aomori Prefectural Central Hospital, 2-1-1 Higashi-tsukurimichi, Aomori 030-8553, Japan Received 1 February 2005
KEYWORDS Fibrosing mediastinitis; TGFb; Immunohistochemistry
Summary Fibrosing mediastinitis is an extremely rare disease in which fibrous tissue is formed progressively within the mediastinum due to various causes. Here, we report two cases of the idiopathic form of fibrosing mediastinitis. We investigated the pathogenesis of fibrosing mediastinitis by immunohistochemical methods, and demonstrated the expression of transforming growth factor b in this disease. These results suggest that transforming growth factor b plays an important role in the pathogenesis of fibrosing mediastinitis. & 2005 Elsevier Ltd. All rights reserved.
Introduction Fibrosing mediastinitis is a very rare disease characterized by progressive fibrous tissue within the mediastinum. Patients with this disease show various signs and symptoms due to obstruction of vital mediastinal organs. Although host responses against infection may cause fibrosing mediastinitis, most patients are idiopathic.1 Here, we report two Corresponding author. Tel.: +81 22 222 6181;
fax: +81 22 267 0856. E-mail address: [email protected] (O. Ishimoto).
cases of fibrosing mediastinitis along with the results of our investigation of the pathogenesis of this disease by immunohistochemical methods.
Patients and methods Case 1 A 53-year-old man was referred to our hospital complaining of hoarseness. Physical examination and laboratory test results were normal, including soluble interleukin-2 receptor, other
1744-9049/$ - see front matter & 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.rmedx.2005.05.003
ARTICLE IN PRESS 72
O. Ishimoto et al. results of percutaneous needle biopsy of the mass. Prednisolone was administered daily at a dose of 30 mg for 1 month. Slight improvement of the lesion was observed in chest MRI, but regrowth of the mass was observed 1 year later when reducing the dose of prednisolone.
Methods
Figure 1 (A) Chest computed tomography scan of Case 1 showing a mass surrounding the aorta. (B) Chest magnetic resonance imaging showing fibrotic tissue around the superior vena cava and the descending aorta in Case 2.
tumor markers, and b-D-glucan. Anti-histoplasma antibody in the serum was negative. Plasma level of transforming growth factor b1 (TGFb1) was high (42.7 ng/ml). Laryngoscopy revealed paralysis of his left vocal cord. A chest computed tomography (CT) scan revealed a mass surrounding the aorta (Fig. 1(A)). Video-assisted thoracoscopic biopsy of the mass was performed and a diagnosis of fibrosing mediastinitis was made. Prednisolone was administered daily at a dose of 30 mg for 2 months; the dose is currently being reduced in a stepwise fashion. Chest CT showed slight shrinkage of the lesion and no relapse was observed over a two-year period.
Case 2 A 60-year-old man complained of palpitation showing systolic heart murmurs in his apex and pitting edema on both legs. Echocardiogram indicated atrial fibrillation. Laboratory test results were normal except for increased white blood cells (10,300/ml) and a high level of C-reactive protein (14.4 mg/dl). Chest magnetic resonance imaging (MRI) showed a mass around the superior vena cava and the descending aorta (Fig. 1(B)). A diagnosis of fibrosing mediastinitis was made based on the
Tissue samples from biopsies of the lesions were fixed in formalin and embedded in paraffin. The paraffin-embedded sections were stained with hematoxylin and eosin (HE) by standard methods. Immunohistochemical staining was performed with an automated slide stainer (BenchMarkTM, Ventana Medical Systems, Inc., Tucson, AZ) using the avidin-biotin-peroxidase complex method with a Basic DAB Detection Kit (Ventana Medical Systems). The primary antibodies used in this study were mouse anti-CD3, anti-CD20, anti-CD45RO, anti-CD68, anti-CD79a, anti-vimentin monoclonal antibodies (CONFORMTM, Ventana Medical Systems), and rabbit anti-TGFb1 polyclonal antibody (Santa Cruz Biotechnology, Santa Cruz, CA). Negative control sections were treated with nonimmune rabbit IgG (Santa Cruz Biotechnology) instead of anti-TGFb1 antibody.
Results HE staining of the biopsy specimens from Cases 1 and 2 showed abundant fibrous tissue infiltrating mediastinal adipose tissue (Fig. 2(A) and (C)). This fibrous tissue was composed mainly of hyalinized collagen fibers with patchy infiltrates of fibrocytes, lymphocytes, and other inflammatory cells. Although lymphocytes and plasma cells formed lymphoid follicles in parts of the lesions, staining for CD3, CD20, CD45RO, and CD79a did not show monoclonal proliferation of lymphocytes. These findings were compatible with fibrosing mediastinitis. Immunohistochemical staining revealed the presence of many vimentin-positive spindle cells. In addition, staining with anti-CD68 antibody revealed abundant macrophages exist among these inflammatory cells. We also found many macrophages express TGFb1, a cytokine that induces fibrosis (Fig. 2(B) and (D)).
Discussion Flieder and colleagues investigated the idiopathic form of fibrosing mediastinitis by histopathological
ARTICLE IN PRESS TGFb in fibrosing mediastinitis
73
Figure 2 Hematoxylin and eosin staining of biopsy specimens from Case 1 (A) and Case 2 (C) demonstrated fibrous tissues with abundant collagen fibers and inflammatory cells infiltrating into the mediastinum. Many macrophages in both Case 1 (B) and Case 2 (D) showed positive staining with anti-TGFb1 antibody.
and immunohistochemical methods.2 They investigated the histopathological patterns in 30 cases and found three groups (stages), and they suggested that these groups were quite similar to an abnormal wound healing process leading to keloid formation. Group I lesions predominantly show edematous fibromyxoid tissue that is similar to granulation tissue. Group II is composed of thick, glassy bands of eosinophilic hyaline material that encircle and infiltrate the mediastinum, which resembles cutaneous keloid. Group III consists of obliterative lesions of dense acellular collagen extending into mediastinal and pulmonary structures, similar to keloid. Vimentin-positive spindle cells are abundant in the lesions in group I, but group II contains fewer of these cells. Therefore, the histological pattern in our patients was consistent with group II. The pathogenesis of fibrosing mediastinitis remains speculative, but some cases are associated with Histoplasma capsulatum infection. Some cases
may be related to other fungi, tuberculosis, or collagen diseases. However, other patients have no signs of these diseases and were diagnosed with idiopathic fibrosing mediastinitis (sclerosing mediastinitis, mediastinal fibrosis). Our patients received a diagnosis of idiopathic fibrosing mediastinitis because neither infection nor collagen diseases were detected. We found macrophages expressing TGFb1, one of the three isoforms of TGFb, in the lesions of fibrosing mediastinitis. TGFb is a multifunctional cytokine that affects cell proliferation and differentiation, migration, angiogenesis, adhesion, extra matrix formation, and immune function. It is secreted by various cell types, such as macrophages, monocytes, platelets, and megakaryocytes.3 Recent studies have suggested that keloid formation is mediated partly by TGFb since TGFb is expressed at high levels in keloid. Thus, downregulation of TGFb is a possible strategy to reduce wound scarring.4 Tamoxifen, a selective estrogen
ARTICLE IN PRESS 74 antagonist, decreases keloid fibroblast proliferation and collagen synthesis by decreasing TGFb production in aberrant wound healing seen with keloid.5,6 As the pathological characteristics are similar between keloid and fibrosing mediastinitis, as described above, tamoxifen may be a candidate drug for fibrosing mediastinitis. In fact, in a previous case report, tamoxifen was reported to be effective in the treatment of fibrosing mediastinitis.7 To our knowledge, this is the first report of the expression of TGFb in fibrosing mediastinitis. The histological analogy to keloid suggested that TGFb plays an important role in the pathogenesis of fibrosing mediastinitis. Thus, regulation of TGFb may be of therapeutic benefit for fibrosing mediastinitis.
Acknowledgements The authors thank Misae Hiyama (Department of Pathology, Aomori Prefectural Central Hospital) for the immunohistochemical staining. This study was
O. Ishimoto et al. supported partly by a research funding from Aomori Prefectural Central Hospital.
References 1. Rossi SE, McAdams HP, Rosado-de-Christenson ML, Franks TJ, Galvin JR. Fibrosing Mediastinitis. Radiographics 2001;21: 737–57. 2. Flieder DB, Suster S, Moran CA. Idiopathic fibroinflammatory (fibrosing/sclerosing) lesions of the mediastinum: a study of 30 cases with emphasis on morphologic heterogeneity. Mod Pathol 1999;12:257–64. 3. Bartram U, Speer CP. The role of transforming growth factor b in lung development and disease. Chest 2004;125:754–65. 4. Liu W, Wang DR, Cao YL. TGFb: a fibrotic factor in wound scarring and a potential target for anti-scarring gene therapy. Curr Gene Ther 2004;4:123–36. 5. Mikulec AA, Hanasono MM, Lum J, Kadleck JM, Kita M, Koch RJ. Effect of tamoxifen on transforming growth factor beta1 production by keloid and fetal fibroblasts. Arch Facial Plast Surg 2001;3:111–4. 6. Chau D, Mancoll JS, Lee S, et al. Tamoxifen downregulates TGFb production in keloid fibroblasts. Ann Plast Surg 1998; 40:490–3. 7. Savelli BA, Parshley M, Morganroth ML. Successful treatment of sclerosing cervicitis and fibrosing mediastinitis with tamoxifen. Chest 1997;111:1137–40.
respiratory MEDICINE Extra
CASE REPORT
Expression of transforming growth factor b in idiopathic fibrosing mediastinitis Osamu Ishimotoa,, Nobuyuki Satob, Tadashi Imaib, Mitsuomi Kaimoric, Akio Ebinab a
Department of Respiratory Medicine, Sendai Kosei Hospital, 4-15 Hirosemachi, Aobaku, Sendai, Miyagi 980-0873, Japan b Department of Respiratory Medicine, Aomori Prefectural Central Hospital, 2-1-1 Higashi-tsukurimichi, Aomori 030-8553, Japan c Department of Pathology, Aomori Prefectural Central Hospital, 2-1-1 Higashi-tsukurimichi, Aomori 030-8553, Japan Received 1 February 2005
KEYWORDS Fibrosing mediastinitis; TGFb; Immunohistochemistry
Summary Fibrosing mediastinitis is an extremely rare disease in which fibrous tissue is formed progressively within the mediastinum due to various causes. Here, we report two cases of the idiopathic form of fibrosing mediastinitis. We investigated the pathogenesis of fibrosing mediastinitis by immunohistochemical methods, and demonstrated the expression of transforming growth factor b in this disease. These results suggest that transforming growth factor b plays an important role in the pathogenesis of fibrosing mediastinitis. & 2005 Elsevier Ltd. All rights reserved.
Introduction Fibrosing mediastinitis is a very rare disease characterized by progressive fibrous tissue within the mediastinum. Patients with this disease show various signs and symptoms due to obstruction of vital mediastinal organs. Although host responses against infection may cause fibrosing mediastinitis, most patients are idiopathic.1 Here, we report two Corresponding author. Tel.: +81 22 222 6181;
fax: +81 22 267 0856. E-mail address: [email protected] (O. Ishimoto).
cases of fibrosing mediastinitis along with the results of our investigation of the pathogenesis of this disease by immunohistochemical methods.
Patients and methods Case 1 A 53-year-old man was referred to our hospital complaining of hoarseness. Physical examination and laboratory test results were normal, including soluble interleukin-2 receptor, other
1744-9049/$ - see front matter & 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.rmedx.2005.05.003
ARTICLE IN PRESS 72
O. Ishimoto et al. results of percutaneous needle biopsy of the mass. Prednisolone was administered daily at a dose of 30 mg for 1 month. Slight improvement of the lesion was observed in chest MRI, but regrowth of the mass was observed 1 year later when reducing the dose of prednisolone.
Methods
Figure 1 (A) Chest computed tomography scan of Case 1 showing a mass surrounding the aorta. (B) Chest magnetic resonance imaging showing fibrotic tissue around the superior vena cava and the descending aorta in Case 2.
tumor markers, and b-D-glucan. Anti-histoplasma antibody in the serum was negative. Plasma level of transforming growth factor b1 (TGFb1) was high (42.7 ng/ml). Laryngoscopy revealed paralysis of his left vocal cord. A chest computed tomography (CT) scan revealed a mass surrounding the aorta (Fig. 1(A)). Video-assisted thoracoscopic biopsy of the mass was performed and a diagnosis of fibrosing mediastinitis was made. Prednisolone was administered daily at a dose of 30 mg for 2 months; the dose is currently being reduced in a stepwise fashion. Chest CT showed slight shrinkage of the lesion and no relapse was observed over a two-year period.
Case 2 A 60-year-old man complained of palpitation showing systolic heart murmurs in his apex and pitting edema on both legs. Echocardiogram indicated atrial fibrillation. Laboratory test results were normal except for increased white blood cells (10,300/ml) and a high level of C-reactive protein (14.4 mg/dl). Chest magnetic resonance imaging (MRI) showed a mass around the superior vena cava and the descending aorta (Fig. 1(B)). A diagnosis of fibrosing mediastinitis was made based on the
Tissue samples from biopsies of the lesions were fixed in formalin and embedded in paraffin. The paraffin-embedded sections were stained with hematoxylin and eosin (HE) by standard methods. Immunohistochemical staining was performed with an automated slide stainer (BenchMarkTM, Ventana Medical Systems, Inc., Tucson, AZ) using the avidin-biotin-peroxidase complex method with a Basic DAB Detection Kit (Ventana Medical Systems). The primary antibodies used in this study were mouse anti-CD3, anti-CD20, anti-CD45RO, anti-CD68, anti-CD79a, anti-vimentin monoclonal antibodies (CONFORMTM, Ventana Medical Systems), and rabbit anti-TGFb1 polyclonal antibody (Santa Cruz Biotechnology, Santa Cruz, CA). Negative control sections were treated with nonimmune rabbit IgG (Santa Cruz Biotechnology) instead of anti-TGFb1 antibody.
Results HE staining of the biopsy specimens from Cases 1 and 2 showed abundant fibrous tissue infiltrating mediastinal adipose tissue (Fig. 2(A) and (C)). This fibrous tissue was composed mainly of hyalinized collagen fibers with patchy infiltrates of fibrocytes, lymphocytes, and other inflammatory cells. Although lymphocytes and plasma cells formed lymphoid follicles in parts of the lesions, staining for CD3, CD20, CD45RO, and CD79a did not show monoclonal proliferation of lymphocytes. These findings were compatible with fibrosing mediastinitis. Immunohistochemical staining revealed the presence of many vimentin-positive spindle cells. In addition, staining with anti-CD68 antibody revealed abundant macrophages exist among these inflammatory cells. We also found many macrophages express TGFb1, a cytokine that induces fibrosis (Fig. 2(B) and (D)).
Discussion Flieder and colleagues investigated the idiopathic form of fibrosing mediastinitis by histopathological
ARTICLE IN PRESS TGFb in fibrosing mediastinitis
73
Figure 2 Hematoxylin and eosin staining of biopsy specimens from Case 1 (A) and Case 2 (C) demonstrated fibrous tissues with abundant collagen fibers and inflammatory cells infiltrating into the mediastinum. Many macrophages in both Case 1 (B) and Case 2 (D) showed positive staining with anti-TGFb1 antibody.
and immunohistochemical methods.2 They investigated the histopathological patterns in 30 cases and found three groups (stages), and they suggested that these groups were quite similar to an abnormal wound healing process leading to keloid formation. Group I lesions predominantly show edematous fibromyxoid tissue that is similar to granulation tissue. Group II is composed of thick, glassy bands of eosinophilic hyaline material that encircle and infiltrate the mediastinum, which resembles cutaneous keloid. Group III consists of obliterative lesions of dense acellular collagen extending into mediastinal and pulmonary structures, similar to keloid. Vimentin-positive spindle cells are abundant in the lesions in group I, but group II contains fewer of these cells. Therefore, the histological pattern in our patients was consistent with group II. The pathogenesis of fibrosing mediastinitis remains speculative, but some cases are associated with Histoplasma capsulatum infection. Some cases
may be related to other fungi, tuberculosis, or collagen diseases. However, other patients have no signs of these diseases and were diagnosed with idiopathic fibrosing mediastinitis (sclerosing mediastinitis, mediastinal fibrosis). Our patients received a diagnosis of idiopathic fibrosing mediastinitis because neither infection nor collagen diseases were detected. We found macrophages expressing TGFb1, one of the three isoforms of TGFb, in the lesions of fibrosing mediastinitis. TGFb is a multifunctional cytokine that affects cell proliferation and differentiation, migration, angiogenesis, adhesion, extra matrix formation, and immune function. It is secreted by various cell types, such as macrophages, monocytes, platelets, and megakaryocytes.3 Recent studies have suggested that keloid formation is mediated partly by TGFb since TGFb is expressed at high levels in keloid. Thus, downregulation of TGFb is a possible strategy to reduce wound scarring.4 Tamoxifen, a selective estrogen
ARTICLE IN PRESS 74 antagonist, decreases keloid fibroblast proliferation and collagen synthesis by decreasing TGFb production in aberrant wound healing seen with keloid.5,6 As the pathological characteristics are similar between keloid and fibrosing mediastinitis, as described above, tamoxifen may be a candidate drug for fibrosing mediastinitis. In fact, in a previous case report, tamoxifen was reported to be effective in the treatment of fibrosing mediastinitis.7 To our knowledge, this is the first report of the expression of TGFb in fibrosing mediastinitis. The histological analogy to keloid suggested that TGFb plays an important role in the pathogenesis of fibrosing mediastinitis. Thus, regulation of TGFb may be of therapeutic benefit for fibrosing mediastinitis.
Acknowledgements The authors thank Misae Hiyama (Department of Pathology, Aomori Prefectural Central Hospital) for the immunohistochemical staining. This study was
O. Ishimoto et al. supported partly by a research funding from Aomori Prefectural Central Hospital.
References 1. Rossi SE, McAdams HP, Rosado-de-Christenson ML, Franks TJ, Galvin JR. Fibrosing Mediastinitis. Radiographics 2001;21: 737–57. 2. Flieder DB, Suster S, Moran CA. Idiopathic fibroinflammatory (fibrosing/sclerosing) lesions of the mediastinum: a study of 30 cases with emphasis on morphologic heterogeneity. Mod Pathol 1999;12:257–64. 3. Bartram U, Speer CP. The role of transforming growth factor b in lung development and disease. Chest 2004;125:754–65. 4. Liu W, Wang DR, Cao YL. TGFb: a fibrotic factor in wound scarring and a potential target for anti-scarring gene therapy. Curr Gene Ther 2004;4:123–36. 5. Mikulec AA, Hanasono MM, Lum J, Kadleck JM, Kita M, Koch RJ. Effect of tamoxifen on transforming growth factor beta1 production by keloid and fetal fibroblasts. Arch Facial Plast Surg 2001;3:111–4. 6. Chau D, Mancoll JS, Lee S, et al. Tamoxifen downregulates TGFb production in keloid fibroblasts. Ann Plast Surg 1998; 40:490–3. 7. Savelli BA, Parshley M, Morganroth ML. Successful treatment of sclerosing cervicitis and fibrosing mediastinitis with tamoxifen. Chest 1997;111:1137–40.