JSTR MEETING NOTES
Extranodal Marginal Zone Lymphoma of Mucosa-associated Lymphoid Tissue of the Central Bronchi Masuo Ujita, MD,* Hideo Sato, MD,w Misako Yamaguchi, MD,w Ken Toba, MD,z and Hiroshi Kobayashi, MDy
Key Words: bronchial neoplasms, mucosa-associated lymphoid tissue lymphoma, computed tomography, immunosuppression
(J Thorac Imaging 2014;29:W91–W93)
E
xtranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a low-grade extranodal lymphoma that arises in the mucosal tissue of various organs, including stomach, salivary gland, or lung. It comprises a majority of primary pulmonary lymphomas but rarely occurs in the bronchial mucosa as an isolated abnormality. We describe a case of MALT lymphoma of the central airways in a patient who has been receiving long-term immunosuppressive agents after renal transplantation and discuss the imaging findings and differential diagnosis.
cleaved nucleus and a moderate amount of clear cytoplasm (Fig. 3). The lymphoepithelial lesions were sparsely seen (Fig. 3B). Immunohistochemical analysis revealed that the proliferated cells were positive for CD20, CD79a, and bcl-2 and negative for CD3, CD68, cyclinD1, CD5, CD10, bcl-6, and CD138. Epstein-Barr virus–encoded small RNA was also negative. On the basis of the morphologic findings and immunohistochemical results, a diagnosis of MALT lymphoma was made. Whole-body imaging disclosed the lesion was confined to the bronchi. In light of the potential disadvantage of surgical resection or chemotherapy in this immunosuppressed patient and the biological nature of low-grade malignancy with MALT lymphoma, watchful waiting was selected as the initial management option. During follow-up, the patient’s symptoms waxed and waned but have gradually improved with only occasional need for bronchodilators. An assessment performed 10 months after the diagnosis showed considerable improvements in both an obstructive defect on spirometry and in the extent of bronchial wall thickening and luminal narrowing at CT.
CASE REPORT
DISCUSSION
A 45-year-old woman who had never smoked presented with a 1-month history of dry cough, wheezing, and dyspnea on exertion. She was afebrile and had no constitutional symptoms such as weight loss or night sweats. Her oxygen saturation in room air was 96%. On chest auscultation, wheezing was heard at both inspiration and expiration most intensively in the left parasternal area. Lung function tests showed %VC 97.9% and FEV1.0/FVC 69.7%. Other laboratory tests were unremarkable. She received a living renal transplant from her father at the age of 23 and has been receiving immunosuppressive medications (azathioprine and tacrolimus) since then. She otherwise had no remarkable previous illnesses or underlying disorder including autoimmune disease. Her chest radiograph was unremarkable; however, unenhanced computed tomography (CT) of the thorax (Fig. 1) demonstrated diffuse wall thickening and irregular luminal narrowing of the airway contiguously from the distal left main bronchus to the segmental and subsegmental bronchi of the left lung (Fig. 1A). The attenuation of the thickened bronchial wall was slightly higher than that of the adjacent vessels or skeletal muscles of the chest wall, but no obvious calcification was seen (Fig. 1B). Neither lung parenchymal abnormalities nor lymph node enlargement was identified. Subsequent fiberoptic bronchoscopy showed nodular mucosal lesions with a cobblestone appearance and dilation of capillary vessels, which led to narrowing of the distal left main bronchus extending to the distal airways (Fig. 2). Microscopic examination of the biopsied specimens demonstrated diffuse and monotonous infiltration in the bronchial wall comprising small to medium-sized lymphocytes, which were characterized by
MALT lymphoma is a low-grade lymphoma that may arise in virtually any extranodal site but most often involves mucosal tissues of the stomach, intestine, ocular adnexa, thyroid, salivary gland, or lung. The disease is closely related to persistent antigenic stimulation with either chronic infections (ie, gastric MALT lymphoma associated with Helicobacter pylori gastritis) or autoimmune diseases (ie, Hashimoto thyroiditis, Sjo¨gren syndrome). MALT lymphoma is clinically indolent and usually remains localized to one of the organs for a prolonged interval, partly because the local accumulation and proliferation of antigen-dependent B cells and T cells play a role in the pathogenic mechanism of MALT lymphoma. However, some patients in the late stage of MALT lymphoma experience spread of the disease to regional lymph nodes, bone marrow, or other extranodal sites. In such cases, the disease may undergo transformation into diffuse large B-cell non-Hodgkin lymphoma. The patient described in this report underwent a living renal transplant 22 years before the onset of MALT lymphoma; therefore, some may consider this case to be a category of posttransplant lymphoproliferative disorders, which were defined as an established entity by the 2008 World Health Organization classification.1 Nevertheless, indolent B-cell lymphomas such as MALT lymphoma are specifically excluded from this category, and Epstein-Barr virus, which is linked with the majority of posttransplant lymphoproliferative disorders,1 was not proven in the bronchial specimen. It is likely that MALT lymphoma developed de novo in the bronchial wall, although the systemic immunologic alteration brought about by the long-term immunosuppressive therapy may, at least in part, have played a role in the etiology of MALT lymphoma in this patient.
From the Departments of *Radiology; wRespiratory Medicine; zHaematology; and yHistopathology, Tachikawa General Hospital, Niigata, Japan. The authors declare no conflicts of interest. Reprints: Masuo Ujita, MD, Department of Radiology, Tachikawa General Hospital 3-2-11 Kandamachi, Nagaoka, Niigata 940-8621 Japan (e-mail: [email protected]). Copyright r 2014 by Lippincott Williams & Wilkins
J Thorac Imaging
Volume 29, Number 6, November 2014
www.thoracicimaging.com |
W91
Ujita et al
J Thorac Imaging
Volume 29, Number 6, November 2014
FIGURE 1. Unenhanced CT of the thorax. A, A high-resolution CT image shows circumferential wall thickening and luminal narrowing extending from the distal left main bronchus to the segmental bronchi of the left upper lobe (arrows). The outer surface of the affected bronchi is smooth. B, The thickened bronchial wall appears of slightly high density on thin-section CT with a mediastinal window setting (width 200; level 50 HU) (arrow). C, A volume rendering display of the airways demonstrates irregular stenosis of the central airways centered on the left hilum.
FIGURE 2. Bronchoscopic view of the distal left main bronchus shows nodular mucosal irregularity and stenosis of the airway toward the secondary carina.
W92 | www.thoracicimaging.com
Although the stomach is the most common site of MALT lymphoma, the lung is frequently involved by the disease and accounts for a majority of primary pulmonary lymphomas that are often associated with autoimmune disorders.2 The CT features of pulmonary MALT lymphoma are well described: the cardinal CT finding is single or multiple nodules or areas of consolidation, which are often bilateral and tend to show a peribronchovascular distribution.2 Other CT features include centrilobular small nodules, bronchial dilation, interlobular septal thickening and/or ground-glass opacification, and thin-walled cysts, all of which overlap with findings of various benign lymphoproliferative disorders typically encountered in patients with Sjo¨gren syndrome.2 In contrast, endobronchial MALT lymphoma at initial presentation is extremely rare, and there have only been a few reports in the literature describing the imaging features of MALT lymphoma solely involving the tracheobronchial tree. Yoon and colleagues reviewed CT images of primary endobronchial MALT lymphoma in 7 patients and categorized the imaging findings into 3 patterns: solitary intraluminal polypoid lesion with or without secondary obstructive change in the lung periphery (4/7 patients); multiple round-shaped nodular protrusions
Extranodal Marginal Zone Lymphoma of Mucosa-associated Lymphoid Tissue of the Central Bronchi Masuo Ujita, MD,* Hideo Sato, MD,w Misako Yamaguchi, MD,w Ken Toba, MD,z and Hiroshi Kobayashi, MDy
Key Words: bronchial neoplasms, mucosa-associated lymphoid tissue lymphoma, computed tomography, immunosuppression
(J Thorac Imaging 2014;29:W91–W93)
E
xtranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is a low-grade extranodal lymphoma that arises in the mucosal tissue of various organs, including stomach, salivary gland, or lung. It comprises a majority of primary pulmonary lymphomas but rarely occurs in the bronchial mucosa as an isolated abnormality. We describe a case of MALT lymphoma of the central airways in a patient who has been receiving long-term immunosuppressive agents after renal transplantation and discuss the imaging findings and differential diagnosis.
cleaved nucleus and a moderate amount of clear cytoplasm (Fig. 3). The lymphoepithelial lesions were sparsely seen (Fig. 3B). Immunohistochemical analysis revealed that the proliferated cells were positive for CD20, CD79a, and bcl-2 and negative for CD3, CD68, cyclinD1, CD5, CD10, bcl-6, and CD138. Epstein-Barr virus–encoded small RNA was also negative. On the basis of the morphologic findings and immunohistochemical results, a diagnosis of MALT lymphoma was made. Whole-body imaging disclosed the lesion was confined to the bronchi. In light of the potential disadvantage of surgical resection or chemotherapy in this immunosuppressed patient and the biological nature of low-grade malignancy with MALT lymphoma, watchful waiting was selected as the initial management option. During follow-up, the patient’s symptoms waxed and waned but have gradually improved with only occasional need for bronchodilators. An assessment performed 10 months after the diagnosis showed considerable improvements in both an obstructive defect on spirometry and in the extent of bronchial wall thickening and luminal narrowing at CT.
CASE REPORT
DISCUSSION
A 45-year-old woman who had never smoked presented with a 1-month history of dry cough, wheezing, and dyspnea on exertion. She was afebrile and had no constitutional symptoms such as weight loss or night sweats. Her oxygen saturation in room air was 96%. On chest auscultation, wheezing was heard at both inspiration and expiration most intensively in the left parasternal area. Lung function tests showed %VC 97.9% and FEV1.0/FVC 69.7%. Other laboratory tests were unremarkable. She received a living renal transplant from her father at the age of 23 and has been receiving immunosuppressive medications (azathioprine and tacrolimus) since then. She otherwise had no remarkable previous illnesses or underlying disorder including autoimmune disease. Her chest radiograph was unremarkable; however, unenhanced computed tomography (CT) of the thorax (Fig. 1) demonstrated diffuse wall thickening and irregular luminal narrowing of the airway contiguously from the distal left main bronchus to the segmental and subsegmental bronchi of the left lung (Fig. 1A). The attenuation of the thickened bronchial wall was slightly higher than that of the adjacent vessels or skeletal muscles of the chest wall, but no obvious calcification was seen (Fig. 1B). Neither lung parenchymal abnormalities nor lymph node enlargement was identified. Subsequent fiberoptic bronchoscopy showed nodular mucosal lesions with a cobblestone appearance and dilation of capillary vessels, which led to narrowing of the distal left main bronchus extending to the distal airways (Fig. 2). Microscopic examination of the biopsied specimens demonstrated diffuse and monotonous infiltration in the bronchial wall comprising small to medium-sized lymphocytes, which were characterized by
MALT lymphoma is a low-grade lymphoma that may arise in virtually any extranodal site but most often involves mucosal tissues of the stomach, intestine, ocular adnexa, thyroid, salivary gland, or lung. The disease is closely related to persistent antigenic stimulation with either chronic infections (ie, gastric MALT lymphoma associated with Helicobacter pylori gastritis) or autoimmune diseases (ie, Hashimoto thyroiditis, Sjo¨gren syndrome). MALT lymphoma is clinically indolent and usually remains localized to one of the organs for a prolonged interval, partly because the local accumulation and proliferation of antigen-dependent B cells and T cells play a role in the pathogenic mechanism of MALT lymphoma. However, some patients in the late stage of MALT lymphoma experience spread of the disease to regional lymph nodes, bone marrow, or other extranodal sites. In such cases, the disease may undergo transformation into diffuse large B-cell non-Hodgkin lymphoma. The patient described in this report underwent a living renal transplant 22 years before the onset of MALT lymphoma; therefore, some may consider this case to be a category of posttransplant lymphoproliferative disorders, which were defined as an established entity by the 2008 World Health Organization classification.1 Nevertheless, indolent B-cell lymphomas such as MALT lymphoma are specifically excluded from this category, and Epstein-Barr virus, which is linked with the majority of posttransplant lymphoproliferative disorders,1 was not proven in the bronchial specimen. It is likely that MALT lymphoma developed de novo in the bronchial wall, although the systemic immunologic alteration brought about by the long-term immunosuppressive therapy may, at least in part, have played a role in the etiology of MALT lymphoma in this patient.
From the Departments of *Radiology; wRespiratory Medicine; zHaematology; and yHistopathology, Tachikawa General Hospital, Niigata, Japan. The authors declare no conflicts of interest. Reprints: Masuo Ujita, MD, Department of Radiology, Tachikawa General Hospital 3-2-11 Kandamachi, Nagaoka, Niigata 940-8621 Japan (e-mail: [email protected]). Copyright r 2014 by Lippincott Williams & Wilkins
J Thorac Imaging
Volume 29, Number 6, November 2014
www.thoracicimaging.com |
W91
Ujita et al
J Thorac Imaging
Volume 29, Number 6, November 2014
FIGURE 1. Unenhanced CT of the thorax. A, A high-resolution CT image shows circumferential wall thickening and luminal narrowing extending from the distal left main bronchus to the segmental bronchi of the left upper lobe (arrows). The outer surface of the affected bronchi is smooth. B, The thickened bronchial wall appears of slightly high density on thin-section CT with a mediastinal window setting (width 200; level 50 HU) (arrow). C, A volume rendering display of the airways demonstrates irregular stenosis of the central airways centered on the left hilum.
FIGURE 2. Bronchoscopic view of the distal left main bronchus shows nodular mucosal irregularity and stenosis of the airway toward the secondary carina.
W92 | www.thoracicimaging.com
Although the stomach is the most common site of MALT lymphoma, the lung is frequently involved by the disease and accounts for a majority of primary pulmonary lymphomas that are often associated with autoimmune disorders.2 The CT features of pulmonary MALT lymphoma are well described: the cardinal CT finding is single or multiple nodules or areas of consolidation, which are often bilateral and tend to show a peribronchovascular distribution.2 Other CT features include centrilobular small nodules, bronchial dilation, interlobular septal thickening and/or ground-glass opacification, and thin-walled cysts, all of which overlap with findings of various benign lymphoproliferative disorders typically encountered in patients with Sjo¨gren syndrome.2 In contrast, endobronchial MALT lymphoma at initial presentation is extremely rare, and there have only been a few reports in the literature describing the imaging features of MALT lymphoma solely involving the tracheobronchial tree. Yoon and colleagues reviewed CT images of primary endobronchial MALT lymphoma in 7 patients and categorized the imaging findings into 3 patterns: solitary intraluminal polypoid lesion with or without secondary obstructive change in the lung periphery (4/7 patients); multiple round-shaped nodular protrusions
