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Primary pulmonary follicular lymphoma
Respiratory Medicine CME 4 (2011) 85e87
Contents lists available at ScienceDirect
Respiratory Medicine CME journal homepage: www.elsevier.com/locate/rmedc
Case Report
Primary pulmonary follicular lymphoma Tadashi Terada* Department of Pathology, Shizuoka City Shimizu Hospital, Miyakami 1231 Shimizu-Ku, Shizuoka 424-8636, Japan
a r t i c l e i n f o
a b s t r a c t
Article history: Received 13 December 2009 Accepted 18 January 2010
Primary malignant lymphomas of the lung are very rare. Most of them are extranodal marginal zone B-cell lymphoma of MALT type. Primary follicular lymphoma of the lung is extremely rare. A 50-year-old woman presented with cough and sputum, and consulted to a private hospital, where she was pointed out to have abnormal lung shadow by chest XeP. She was admitted to our hospital for scrutiny. Imaging modalities including CT, MRI, and PET revealed a small (15 mm in diameter) nodule in the right middle lobe beneath the pleura. No other tumors were found by these techniques. A biopsy revealed a lymphoid proliferation. Clinical cytology was negative. A wedge resection with wide margins was performed. Grossly, the resected lung specimen contained a white solid mass measuring 12 13 13 mm. Microscopically, the mass was composed of follicular proliferation of atypical lymphocytes. There were no tingible body macrophages, and normal follicular polarity was absent. Mild infiltrative growth from the surrounding lung was present. Lymphoepithelial lesions were not recognized. The atypical lymphocytes consisted of centrocytes, centroblasts, and small lymphoid cuffs. The centroblasts are seen in 3e5 per a high power field. The immunophenotypes were CD45 þ, CD5 þ, CD10 þ, CD23 þ, cyclin D1 , CD20 þ, CD21 þ, CD79a þ, bcl-2 þ, bcl-6 , CD3 , CD45RO , CD30 , CD15 , k-chain þ, and l-chain . The Ki-67 labeling was 36%. The overall appearances suggested that the lesion was primary pulmonary follicular lymphoma, grade I. Discussion of differential diagnosis from nodular lymphoid hyperplasia, extranodal marginal zone lymphoma of MALT type, and mantle cell lymphoma was made. Ó 2010 Elsevier Ltd. All rights reserved.
Keywords: Lung Lymphoma Follicular lymphoma Histopathology
1. Introduction Primary pulmonary malignant lymphomas are very rare.1e4 Most of them are extranodal marginal zone B-cell lymphoma of MALT type. Primary pulmonary follicular lymphoma is extremely rare.1,5 The author here reports a case of primary pulmonary follicular lymphoma. This lymphoma was very difficult to differentiate from extranodal marginal B-cell zone lymphoma of MALT type. 2. Case report A 50-year-old woman presented with cough and sputum, and consulted to a private hospital, where she was pointed out to have abnormal lung shadow by chest XeP. She was admitted to our hospital for scrutiny. Imaging modalities including CT, MRI, and PET revealed a small (15 mm in diameter) nodule in the right middle lobe beneath the pleura. No other tumors were found by these techniques. A biopsy revealed a lymphoid proliferation. Clinical cytology was negative.
* Tel.: þ81 54 336 1111; fax: þ81 54 3361315. E-mail address: [email protected]. 1755-0017/$36.00 Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.rmedc.2010.01.009
A video-assisted thoracoscopic wedge resection with wide margins was performed. Grossly, the resected lung specimen contained a white solid mass measuring 12 13 13 mm (Fig. 1). Microscopically, the mass was composed of follicular proliferation of atypical lymphocytes (Fig. 2a and b). Mild infiltrative growth from the surrounding lung was present. There were no tingible body macrophages in the follicles, and the normal polarity of lymphoid follicles is absent. Lymphoepithelial lesions were not recognized. The atypical lymphocytes consisted of centrocytes, centroblasts, and small lymphoid cuffs (Fig. 2b and c). The centroblasts are seen in 3e5 per a high power field (Fig. 2c). An immunohistochemical study was performed with the use of Dako Envision method, as previously described.6e8 The antibodies used were as follows: cytokeratins (AE1/3, Dako, Glostrup, Denmark), cytokeratin (CAM5.2, Bekton-Dickinson, CA, USA), CD45 (LCA, Dako), CD20 (L26, Dako), CD79a (SN8, Dako), CD21 (1F8, Dako), CD23 (MHM6, Dako), cyclin D1 (DCS-22, Dako), bcl-2 (124, Dako), bcl-6 (PG-B6P, Dako), CD5 (DK23, Dako), CD10 (SS2/6, Dako), CD3 (PC3/188A, Dako), CD45RO (UCHL-1, Dako), CD30 (Ber-H2, Dako), CD15 (C34D1, Dako), k-chain (polyclonal, Dako), l-chain (polyclonal, Dako). The tumor cells were negative for cytokeratins. The immunophenotypes of the lymphocytes in the present tumor were as
86
T. Terada / Respiratory Medicine CME 4 (2011) 85e87
Fig. 1. Gross features. A solid white tumor measuring 12 13 13 mm is present beneath the pleura.
follows: CD45 þþþ, CD20 þþþ Fig. 3a, bcl-2 þþþ (Fig. 3b), CD5 þ (Fig. 3c), CD10 þ (Fig. 3d), CD23 þþ (Fig. 3e), cyclin D1 , CD21 þ, CD79a þ, bcl-6 , CD3 , CD45RO , CD30 , CD15 , k-chain þþ Fig. 3f, and l-chain . The Ki-67 labeling was 36%. The overall appearances suggested that the lesion was primary pulmonary follicular lymphoma, grade I. The surgical margins of the resected lung were free of tumor cells. The patient is now free of disease three months after the operation, and is carefully follow-up with a low dose of chemotherapy. 3. Discussion Primary pulmonary follicular lymphoma is extremely rare. Graham et al.1 reported that of the 18 primary pulmonary lymphomas 16 were extranodal marginal zone B-cell lymphomas, 1 was Hodgkin’s disease, and 1 was follicular lymphoma. Ferraro et al.3 who examined 48 patients with primary pulmonary lymphomas showed that the lymphoma type was extranodular marginal zone B-cell lymphoma of MALT type in 35 cases and other types in 13 cases. Other studies did not found follicular lymphoma in pulmonary lymphomas.2,4 Pulmonary follicular lymphoma is very difficult to differentiate from extranodal marginal zone B-cell lymphoma of MALT type.5 In the present study, the tumor consisted of follicular structures. The follicles lacked tingible body macrophages and the normal follicular polarity. The presence of bcl-2 strongly suggests that the present tumor is follicular lymphoma. In the present study, the immunophenotypes of the follicles were as follows: CD45 þþþ, CD20 þþþ, bcl-2 þþþ, CD5 þ, CD10 þ, CD23 þþ, cyclin D1 , CD21 þ, CD79a þ, bcl-6 , CD3 , CD45RO , CD30 , CD15 , k-chain þþ, and l-chain . In general, immunophenotype of follicular lymphoma is as follows: bcl-2 þ, CD10 þ, CD20 þ, CD19 þ, CD 22 þ, CD79a þ, bcl-6 þ, CD21 þ, CD23 þ, cyclin D1 .9 Despite of some exceptions, the present case appears to mostly resemble follicular lymphoma. First, the present case should be differentiated from pulmonary reactive lymphoid proliferation such as nodular lymphoid hyperplasia.10,11 This disease is frequently associated with Sjogren syndrome. The present case consisted of only B-cells, and T-cells as detected by CD3 and CD45RO were almost none, suggesting a monoclonality of the proliferating lymphocytes. In addition, the presence of light chain restriction (k-chain þþ, and l-chain ) in the present case strongly suggests the monoclonality of the lesion. Furthermore, positive bcl-2 protein in the present study excludes
Fig. 2. Microscopic features. a: Low power view. The tumor consists of lymphoid cells with multifollicular appearances. HE, 40. b: Middle power view. The follicles were composed of germinal center-like pale zones and surrounding marginal zone like dark zone. HE, 100. c: High power view. The tumor cells consisted of many centrocytes and a few centroblasts. HE, 200.
reactive hyperplasia, because bcl-2 protein is not expressed in the reactive lymphoid hyperplasia.9 Histologically, the absence of tingible body macrophages and the absence of follicular polarity favor the neoplasmic natures of the present tumor. The Ki-67 labeling was 36% in the present case, suggesting a neoplasmic nature of the present tumor. Second, the present case is difficult to differentiate from extranodal marginal zone B-cell lymphoma, the most common
T. Terada / Respiratory Medicine CME 4 (2011) 85e87
87
Fig. 3. Immunohistochemical findings. a: The many follicles are positive for CD20.40. b: Each follicle is positive for bcl-2. 100. c: CD 5-positive cells are scattered in each follicle. 100. d: CD10-positive cells are scattered in each follicle. 100. e: There are many CD23-positive cells in each follicle. 100. f: The follicle cells are positive predominantly for kchain. 100.
pulmonary lymphoma.1e4 This tumor is histologically characterized by proliferation of centrocyte-like cells, plasma cell, monocytoid B-cells, lymphoepithelial lesions, and formation of germinal centers.12 In the present case, such typical histological features of this neoplasm were absent. In addition, the positivity of bcl-2 in the follicles in the present case strongly suggests that the tumor is not extranodal marginal zone B-cell lymphoma. In general, this neoplasm shows the following immunophenotypes: CD20 þ, CD79a þ, CD5 , CD10 , CD23 , CD43 þ/, CD11C þ/, CD35 þ, CD21 þ, cyclin D1 .12 This profile is different from the present case. Therefore, the author thinks that the present tumor is not extranodal marginal zone B-cell lymphoma of MALT type. Third, differentiation from a low grade B-cell lymphoma, mantle cell lymphoma, is important. This neoplasm shows neoplasmic proliferation of mantle zone lymphoma. Mantle cell lymphoma may show nodular patterns, but the histological appearances of the present tumor are different from mantle cell lymphoma. Mantle cell lymphoma characteristically expressed cyclin D1,13 but the present tumor lacked this molecule. The immunophenotypes of mantle cell lymphoma are as follows: CD5 þ, CD10 , bcl-6 , CD23 , CD43 þ, CD21 þ, CD35 þ, and cyclin D1 þ. The immunohistochemical features of the present case are different from those of mantle cell lymphoma. Therefore, the present case is not mantle cell lymphoma. Finally, the present study did not investigate molecular genetic study. More molecular studies including Immunoglobulin rearrangement and bcl-2 rearrangement are necessary in the future study. Conflict of interest statement The author has no conflict of interest.
References 1. Graham BB, Mathisen DJ, Mark EJ, Takvorian RW. Primary pulmonary lymphoma. Ann Thrac Surg 2005;80:1248e53. 2. Tamura A, Komatsu H, Yanai N, et al. Primary pulmonary lymphoma: relationship between clinical features and pathologic findings in 24 cases. Jpn J Clin Oncol 1995;25:140e52. 3. Ferrero P, Trasteck VF, Adlakha H, Deschamps C, Allen MS, Pairolero PC. Primary non-Hodgkin’s lymphoma of the lung. Ann Thrac Surg 2000;69:993e7. 4. Kim JH, Lee SH, Park J, et al. Primary pulmonary non-Hodgkin’s lymphoma. Jpn J Clin Oncol 2004;34:510e4. 5. Jourdan F, Molina TJ, Le Tourneau A, Machet MC, De Muret A, Renjard L, et al. Florid marginal zone differentiation in follicular lymphoma mimicking marginal zone lymphoma of MALT type in the lung. Histopathology 2006;49:426e9. 6. Terada T, Kawaguchi M, Furukawa K, Sekido Y, Osamura RY. Minute mixed ductal-endocrine carcinoma of the pancreas with predominant intraductal growth. Pathol Int 2002;52:740e6. 7. Terada T, Kawaguchi M. Primary clear cell adenocarcinoma of the peritoneum. Tohoku J Exp Med 2005;206:271e5. 8. Terada T, Taniguchi M. Intraductal oncocytic papillary neoplasm of the liver. Pathol Int 2004;54:116e23. 9. Nathwani BN, Pilis MA, Harris NL, et al. Follicular lymphoma. In: Jaffe ES, Harris NL, Stein H, Vardiman JW, editors. World Health Organization classification of tumours. Pathology and genetics of tumours of haematopoietic and lymphoid tissues. Lyon: IARC Press; 2001. p. 162e7. 10. Abbondanzo SL, Rush W, Bijwaard KE, Koss MN. Nodular lymphoid hyperplasia of the lung: a clinicopathologic study of 14 cases. Am J Surg Pathol 2000;24:587e97. 11. Sakurai H, Handa M, Oyama T. Nodular lymphoid hyperplasia of the lung: a very rare disease entity. Ann Thorac Surg 2007;83:2197e9. 12. Isaacson PG, Berger F, MullerpHermelink HK, et al. Extranodal marginal zone B-cell lymphoma of mucosa-assiciated lymphoid tissue (MALT lymphoma). In: Jaffe ES, Harris NL, Stein H, Vardiman JW, editors. World Health Organization classification of tumours. Pathology and genetics of tumours of haematopoietic and lymphoid tissues. Lyon: IARC Press; 2001. p. 157e60. 13. Swerdlow SH, Nathwari BN, Berger F, et al. Mantle cell lymphoma. In: Jaffe ES, Harris NL, Stein H, Vardiman JW, editors. World Health Organization classification of tumours. Pathology and genetics of tumours of haematopoietic and lymphoid tissues. Lyon: IARC Press; 2001. p. 168e74.
Contents lists available at ScienceDirect
Respiratory Medicine CME journal homepage: www.elsevier.com/locate/rmedc
Case Report
Primary pulmonary follicular lymphoma Tadashi Terada* Department of Pathology, Shizuoka City Shimizu Hospital, Miyakami 1231 Shimizu-Ku, Shizuoka 424-8636, Japan
a r t i c l e i n f o
a b s t r a c t
Article history: Received 13 December 2009 Accepted 18 January 2010
Primary malignant lymphomas of the lung are very rare. Most of them are extranodal marginal zone B-cell lymphoma of MALT type. Primary follicular lymphoma of the lung is extremely rare. A 50-year-old woman presented with cough and sputum, and consulted to a private hospital, where she was pointed out to have abnormal lung shadow by chest XeP. She was admitted to our hospital for scrutiny. Imaging modalities including CT, MRI, and PET revealed a small (15 mm in diameter) nodule in the right middle lobe beneath the pleura. No other tumors were found by these techniques. A biopsy revealed a lymphoid proliferation. Clinical cytology was negative. A wedge resection with wide margins was performed. Grossly, the resected lung specimen contained a white solid mass measuring 12 13 13 mm. Microscopically, the mass was composed of follicular proliferation of atypical lymphocytes. There were no tingible body macrophages, and normal follicular polarity was absent. Mild infiltrative growth from the surrounding lung was present. Lymphoepithelial lesions were not recognized. The atypical lymphocytes consisted of centrocytes, centroblasts, and small lymphoid cuffs. The centroblasts are seen in 3e5 per a high power field. The immunophenotypes were CD45 þ, CD5 þ, CD10 þ, CD23 þ, cyclin D1 , CD20 þ, CD21 þ, CD79a þ, bcl-2 þ, bcl-6 , CD3 , CD45RO , CD30 , CD15 , k-chain þ, and l-chain . The Ki-67 labeling was 36%. The overall appearances suggested that the lesion was primary pulmonary follicular lymphoma, grade I. Discussion of differential diagnosis from nodular lymphoid hyperplasia, extranodal marginal zone lymphoma of MALT type, and mantle cell lymphoma was made. Ó 2010 Elsevier Ltd. All rights reserved.
Keywords: Lung Lymphoma Follicular lymphoma Histopathology
1. Introduction Primary pulmonary malignant lymphomas are very rare.1e4 Most of them are extranodal marginal zone B-cell lymphoma of MALT type. Primary pulmonary follicular lymphoma is extremely rare.1,5 The author here reports a case of primary pulmonary follicular lymphoma. This lymphoma was very difficult to differentiate from extranodal marginal B-cell zone lymphoma of MALT type. 2. Case report A 50-year-old woman presented with cough and sputum, and consulted to a private hospital, where she was pointed out to have abnormal lung shadow by chest XeP. She was admitted to our hospital for scrutiny. Imaging modalities including CT, MRI, and PET revealed a small (15 mm in diameter) nodule in the right middle lobe beneath the pleura. No other tumors were found by these techniques. A biopsy revealed a lymphoid proliferation. Clinical cytology was negative.
* Tel.: þ81 54 336 1111; fax: þ81 54 3361315. E-mail address: [email protected]. 1755-0017/$36.00 Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.rmedc.2010.01.009
A video-assisted thoracoscopic wedge resection with wide margins was performed. Grossly, the resected lung specimen contained a white solid mass measuring 12 13 13 mm (Fig. 1). Microscopically, the mass was composed of follicular proliferation of atypical lymphocytes (Fig. 2a and b). Mild infiltrative growth from the surrounding lung was present. There were no tingible body macrophages in the follicles, and the normal polarity of lymphoid follicles is absent. Lymphoepithelial lesions were not recognized. The atypical lymphocytes consisted of centrocytes, centroblasts, and small lymphoid cuffs (Fig. 2b and c). The centroblasts are seen in 3e5 per a high power field (Fig. 2c). An immunohistochemical study was performed with the use of Dako Envision method, as previously described.6e8 The antibodies used were as follows: cytokeratins (AE1/3, Dako, Glostrup, Denmark), cytokeratin (CAM5.2, Bekton-Dickinson, CA, USA), CD45 (LCA, Dako), CD20 (L26, Dako), CD79a (SN8, Dako), CD21 (1F8, Dako), CD23 (MHM6, Dako), cyclin D1 (DCS-22, Dako), bcl-2 (124, Dako), bcl-6 (PG-B6P, Dako), CD5 (DK23, Dako), CD10 (SS2/6, Dako), CD3 (PC3/188A, Dako), CD45RO (UCHL-1, Dako), CD30 (Ber-H2, Dako), CD15 (C34D1, Dako), k-chain (polyclonal, Dako), l-chain (polyclonal, Dako). The tumor cells were negative for cytokeratins. The immunophenotypes of the lymphocytes in the present tumor were as
86
T. Terada / Respiratory Medicine CME 4 (2011) 85e87
Fig. 1. Gross features. A solid white tumor measuring 12 13 13 mm is present beneath the pleura.
follows: CD45 þþþ, CD20 þþþ Fig. 3a, bcl-2 þþþ (Fig. 3b), CD5 þ (Fig. 3c), CD10 þ (Fig. 3d), CD23 þþ (Fig. 3e), cyclin D1 , CD21 þ, CD79a þ, bcl-6 , CD3 , CD45RO , CD30 , CD15 , k-chain þþ Fig. 3f, and l-chain . The Ki-67 labeling was 36%. The overall appearances suggested that the lesion was primary pulmonary follicular lymphoma, grade I. The surgical margins of the resected lung were free of tumor cells. The patient is now free of disease three months after the operation, and is carefully follow-up with a low dose of chemotherapy. 3. Discussion Primary pulmonary follicular lymphoma is extremely rare. Graham et al.1 reported that of the 18 primary pulmonary lymphomas 16 were extranodal marginal zone B-cell lymphomas, 1 was Hodgkin’s disease, and 1 was follicular lymphoma. Ferraro et al.3 who examined 48 patients with primary pulmonary lymphomas showed that the lymphoma type was extranodular marginal zone B-cell lymphoma of MALT type in 35 cases and other types in 13 cases. Other studies did not found follicular lymphoma in pulmonary lymphomas.2,4 Pulmonary follicular lymphoma is very difficult to differentiate from extranodal marginal zone B-cell lymphoma of MALT type.5 In the present study, the tumor consisted of follicular structures. The follicles lacked tingible body macrophages and the normal follicular polarity. The presence of bcl-2 strongly suggests that the present tumor is follicular lymphoma. In the present study, the immunophenotypes of the follicles were as follows: CD45 þþþ, CD20 þþþ, bcl-2 þþþ, CD5 þ, CD10 þ, CD23 þþ, cyclin D1 , CD21 þ, CD79a þ, bcl-6 , CD3 , CD45RO , CD30 , CD15 , k-chain þþ, and l-chain . In general, immunophenotype of follicular lymphoma is as follows: bcl-2 þ, CD10 þ, CD20 þ, CD19 þ, CD 22 þ, CD79a þ, bcl-6 þ, CD21 þ, CD23 þ, cyclin D1 .9 Despite of some exceptions, the present case appears to mostly resemble follicular lymphoma. First, the present case should be differentiated from pulmonary reactive lymphoid proliferation such as nodular lymphoid hyperplasia.10,11 This disease is frequently associated with Sjogren syndrome. The present case consisted of only B-cells, and T-cells as detected by CD3 and CD45RO were almost none, suggesting a monoclonality of the proliferating lymphocytes. In addition, the presence of light chain restriction (k-chain þþ, and l-chain ) in the present case strongly suggests the monoclonality of the lesion. Furthermore, positive bcl-2 protein in the present study excludes
Fig. 2. Microscopic features. a: Low power view. The tumor consists of lymphoid cells with multifollicular appearances. HE, 40. b: Middle power view. The follicles were composed of germinal center-like pale zones and surrounding marginal zone like dark zone. HE, 100. c: High power view. The tumor cells consisted of many centrocytes and a few centroblasts. HE, 200.
reactive hyperplasia, because bcl-2 protein is not expressed in the reactive lymphoid hyperplasia.9 Histologically, the absence of tingible body macrophages and the absence of follicular polarity favor the neoplasmic natures of the present tumor. The Ki-67 labeling was 36% in the present case, suggesting a neoplasmic nature of the present tumor. Second, the present case is difficult to differentiate from extranodal marginal zone B-cell lymphoma, the most common
T. Terada / Respiratory Medicine CME 4 (2011) 85e87
87
Fig. 3. Immunohistochemical findings. a: The many follicles are positive for CD20.40. b: Each follicle is positive for bcl-2. 100. c: CD 5-positive cells are scattered in each follicle. 100. d: CD10-positive cells are scattered in each follicle. 100. e: There are many CD23-positive cells in each follicle. 100. f: The follicle cells are positive predominantly for kchain. 100.
pulmonary lymphoma.1e4 This tumor is histologically characterized by proliferation of centrocyte-like cells, plasma cell, monocytoid B-cells, lymphoepithelial lesions, and formation of germinal centers.12 In the present case, such typical histological features of this neoplasm were absent. In addition, the positivity of bcl-2 in the follicles in the present case strongly suggests that the tumor is not extranodal marginal zone B-cell lymphoma. In general, this neoplasm shows the following immunophenotypes: CD20 þ, CD79a þ, CD5 , CD10 , CD23 , CD43 þ/, CD11C þ/, CD35 þ, CD21 þ, cyclin D1 .12 This profile is different from the present case. Therefore, the author thinks that the present tumor is not extranodal marginal zone B-cell lymphoma of MALT type. Third, differentiation from a low grade B-cell lymphoma, mantle cell lymphoma, is important. This neoplasm shows neoplasmic proliferation of mantle zone lymphoma. Mantle cell lymphoma may show nodular patterns, but the histological appearances of the present tumor are different from mantle cell lymphoma. Mantle cell lymphoma characteristically expressed cyclin D1,13 but the present tumor lacked this molecule. The immunophenotypes of mantle cell lymphoma are as follows: CD5 þ, CD10 , bcl-6 , CD23 , CD43 þ, CD21 þ, CD35 þ, and cyclin D1 þ. The immunohistochemical features of the present case are different from those of mantle cell lymphoma. Therefore, the present case is not mantle cell lymphoma. Finally, the present study did not investigate molecular genetic study. More molecular studies including Immunoglobulin rearrangement and bcl-2 rearrangement are necessary in the future study. Conflict of interest statement The author has no conflict of interest.
References 1. Graham BB, Mathisen DJ, Mark EJ, Takvorian RW. Primary pulmonary lymphoma. Ann Thrac Surg 2005;80:1248e53. 2. Tamura A, Komatsu H, Yanai N, et al. Primary pulmonary lymphoma: relationship between clinical features and pathologic findings in 24 cases. Jpn J Clin Oncol 1995;25:140e52. 3. Ferrero P, Trasteck VF, Adlakha H, Deschamps C, Allen MS, Pairolero PC. Primary non-Hodgkin’s lymphoma of the lung. Ann Thrac Surg 2000;69:993e7. 4. Kim JH, Lee SH, Park J, et al. Primary pulmonary non-Hodgkin’s lymphoma. Jpn J Clin Oncol 2004;34:510e4. 5. Jourdan F, Molina TJ, Le Tourneau A, Machet MC, De Muret A, Renjard L, et al. Florid marginal zone differentiation in follicular lymphoma mimicking marginal zone lymphoma of MALT type in the lung. Histopathology 2006;49:426e9. 6. Terada T, Kawaguchi M, Furukawa K, Sekido Y, Osamura RY. Minute mixed ductal-endocrine carcinoma of the pancreas with predominant intraductal growth. Pathol Int 2002;52:740e6. 7. Terada T, Kawaguchi M. Primary clear cell adenocarcinoma of the peritoneum. Tohoku J Exp Med 2005;206:271e5. 8. Terada T, Taniguchi M. Intraductal oncocytic papillary neoplasm of the liver. Pathol Int 2004;54:116e23. 9. Nathwani BN, Pilis MA, Harris NL, et al. Follicular lymphoma. In: Jaffe ES, Harris NL, Stein H, Vardiman JW, editors. World Health Organization classification of tumours. Pathology and genetics of tumours of haematopoietic and lymphoid tissues. Lyon: IARC Press; 2001. p. 162e7. 10. Abbondanzo SL, Rush W, Bijwaard KE, Koss MN. Nodular lymphoid hyperplasia of the lung: a clinicopathologic study of 14 cases. Am J Surg Pathol 2000;24:587e97. 11. Sakurai H, Handa M, Oyama T. Nodular lymphoid hyperplasia of the lung: a very rare disease entity. Ann Thorac Surg 2007;83:2197e9. 12. Isaacson PG, Berger F, MullerpHermelink HK, et al. Extranodal marginal zone B-cell lymphoma of mucosa-assiciated lymphoid tissue (MALT lymphoma). In: Jaffe ES, Harris NL, Stein H, Vardiman JW, editors. World Health Organization classification of tumours. Pathology and genetics of tumours of haematopoietic and lymphoid tissues. Lyon: IARC Press; 2001. p. 157e60. 13. Swerdlow SH, Nathwari BN, Berger F, et al. Mantle cell lymphoma. In: Jaffe ES, Harris NL, Stein H, Vardiman JW, editors. World Health Organization classification of tumours. Pathology and genetics of tumours of haematopoietic and lymphoid tissues. Lyon: IARC Press; 2001. p. 168e74.