Lymphoma of the mucosa-associated lymphoid tissue of the lung. A multifocal case of common clonal origin

Extranodal Marginal Zone Lymphoma of the Lung: Evolution from an Underlying Reactive Lymphoproliferative Disorder

Extranodal Marginal Zone Lymphoma (ENMZL) of Mucosa-Associated Lymphoid Tissue (MALT) is a problematic and sometimes controversial diagnosis. While commonly seen in the stomach in the setting of chronic Helicobacter pylori infection, other extranodal sites, such as the lung, may also present with disease. ENMZL is clinically and morphologically heterogeneous; however, regardless of presentation, the etiology lies in the accumulation of lymphoid tissue in non-traditional sites. This phenomenon is typically secondary to an underlying inflammatory stimulus such as chronic infection or autoimmune states. The current case report details the clinical history of a patient with Sjögren syndrome over a four year period who eventually developed ENMZL. The patient initially presented with an atypical, but polyclonal, lymphoproliferative process diagnosed as lymphocytic interstitial pneumonia. Over time, the patient showed evolution to a monoclonal process with associated radiologic progression of disease. This evolution manifested as a dense lymphoid infiltrate with prominent plasmacytic differentiation and the development of a lung mass radiologically. This case contributes to the growing body of knowledge that suggests ENMZL lies along a biological spectrum of lymphoproliferative disorders whereby a benign, reactive process may eventually undergo malignant transformation. This evolution likely represents the acquisition of genetic abnormalities that allow autonomous proliferation in the absence of the initial immune stimulus. In practice, determining when this event occurs and, thus, distinguishing between reactive and neoplastic disorders within this spectrum may be difficult as no single clinicopathologic feature may be present to establish the diagnosis. This case further illustrates the importance of correlating the clinical, radiologic and pathologic data to evaluate patients with atypical pulmonary lymphoproliferative disorders and to allow the optimal management of their disease.

[Immunophenotyping and gene rearrangement analysis in lymphoid/lymphoproliferative disorders of the lungs]

OBJECTIVE

To determine the usefulness, in routine practice, of using polymerase chain reaction to analyze B and T lymphocyte clonality in pulmonary tissue as a tool for the diagnosis of pulmonary lymphoproliferative disorders.

METHODS

Immunohistochemistry and molecular gene rearrangement analysis were performed in order to assess 8 cases of lymphoid interstitial pneumonia (LIP) and 7 cases of pulmonary lymphoproliferative disorders.

RESULTS

All 8 cases of LIP presented moderate to strong immunostaining for CD3, compared with only 2 cases of lymphoma and 1 case of pseudolymphoma (p = 0.02). Gene rearrangement was detected in 4 of the 8 cases, which changed the diagnosis from LIP to lymphoma, showing the importance of gene rearrangement detection in cases of LIP. In this situation, gene rearrangement using the VH/JH and Vgamma11/Jgamma12 primer pairs was detected in 3 cases and 1 case, respectively, and no gene abnormalities were found using the Dbeta1/Jbeta2 and Vgamma101/Jgamma12 primer pairs in any of the cases. A significant positive association was found between the intensity of CD20 and CD68 expression and gene rearrangement using the VH/JH primer pair. Prior to the gene rearrangement, 4 patients with LIP died quickly, whereas only one patient with LIP died after the gene rearrangement.

CONCLUSIONS

Detection of monoclonal B and T cells by immunophenotyping and polymerase chain reaction had an impact on the diagnosis of pulmonary lymphomas in patients previously diagnosed with LIP. Therefore, immunophenotyping and polymerase chain reaction should be used as 'gold standard' techniques in routine practice.

Pulmonary Pathology for the Clinician

The idiopathic interstitial pneumonias are a group of diffuse parenchymal lung diseases that manifest varying patterns of inflammation and fibrosis histopathologically. These disorders are classified most accurately by the combination of histopathology on lung biopsy with clinical and radiographic findings. A pattern-based approach to the histopathology of the lung biopsy, as examined at low magnification, immediately helps narrow the diagnostic possibilities. The technique can be applied by pulmonologists and pathologists in assembling a cogent differential diagnosis. More subtle histopathologic findings in the biopsy (eg, granulomas, necrosis, eosinophils) help narrow this differential. This pattern-based histopathologic technique fosters close interaction between pulmonologists and general pathologists during the evaluation of the patient who has interstitial lung disease and has undergone surgical biopsy.

Malignant and benign lymphoid lesions of the lung

Lymphoid lesions of the lung produce a complex of problems for the practicing pathologist. Although these lesions are eventually referred to hematopathologists, it is still the general surgical pathologist who first encounters them and confronts the problem of formulating an initial diagnosis. Over the last 20 years there has been a revolution in our knowledge of the classification and natural history of the pulmonary lesions, a plethora of information which warrants a thorough review. The purpose of this discussion is to report the clinical features and courses, pathologic features and, when known, etiologies or pathogenesis of the major "primary" pulmonary lymphoid lesions and present a brief approach to differential diagnosis. I will divide the lesions into malignant and benign, discussing each in turn.

Low-grade B-cell bronchial associated lymphoid tissue (BALT) lymphoma

Low-grade B-cell bronchial associated lymphoid tissue (BALT) lymphoma is a distinct subgroup of non-Hodgkin's lymphoma. Chronic antigen stimulation, triggered by autoimmune process or persistent infection may precede the development of BALT lymphoma. The lymphoma cells originate from the marginal zone and by invading the bronchial epithelial tissue, give rise to the lymphoepithelial lesion. BALT lymphoma shares the morphologic, immunophenotypic, and cytogenetic characteristics of other mucosa associated lymphoid tissue lymphomas. A majority of the patients are asymptomatic and pulmonary lesions are incidentally discovered on a routine chest radiograph. However, the clinical and radiographic features of BALT lymphoma are nonspecific. The disease is often localized at the time of diagnosis and responds favorably to local treatment, but the optimal management is not clearly defined. Overall, BALT lymphoma has a favorable prognosis and is associated with long-term survival.

Multiple organ mucosa-associated lymphoid tissue lymphomas often involve the intestine

BACKGROUND

Low grade mucosa-associated lymphoid tissue (MALT) lymphomas usually are confined to single extranodal organs. Although some case reports have been published, clinicopathologic characteristics of multiorgan MALT lymphomas remain unclear.

METHODS

The authors evaluated 7 MALT lymphoma cases involving multiorgans in the past 7 years. In this period, they experienced 304 cases of MALT lymphomas. They analyzed the clinicopathologic features of these cases, including examination of clonal comparison among the lesions.

RESULTS

The patients, 4 females and 3 males, were aged 55-68 years old (average, 60.1 years). Four cases showed multiple organ involvement at the initial diagnosis or after a short period. In the other three cases, primary foci were the stomach, thyroid gland, and ocular adnexa; after a rather long period (3 years or more), distant metastases were found. Although intestinal primary lymphomas are rather rare, six of the seven cases showed large intestinal involvement. Lymph node involvement was proven in only three cases. The patients were rather resistant to the various therapeutic approaches. Although six patients are alive, five are with disease. DNA analyses revealed that in five of the cases evaluated, identical clones were detected among the different affected organs.

CONCLUSIONS

Multiorgan MALT lymphomas are rather rare. Most cases probably derived from a single clone, and lymphoma cells may selectively move among MALTs via a homing system with preferential involvement of the colon. Because multiorgan MALT lymphomas rarely achieve complete remission by treatment with combination chemotherapy or irradiation, MALT lymphomatous lesions should be checked carefully, especially in the large intestine.

B-cell pulmonary lymphoma: gene rearrangement analysis of bronchoalveolar lymphocytes by polymerase chain reaction

STUDY OBJECTIVES

Non-Hodgkin's lymphomas (NHLs) are clonal proliferation of B or T lymphocytes. Assessment of clonality in lymphoid proliferations uses immunochemistry and, recently, molecular biology. The aim of our study is to assess the role of immunoglobulin gene rearrangement analysis on bronchoalveolar lymphocytes to aid in the diagnosis of B-cell pulmonary NHL.

PATIENTS AND METHODS

The study took place in a university hospital. There were seven consecutive patients with B-cell-type pulmonary lymphoma and nine control subjects. Gene rearrangement analysis using polymerase chain reaction (PCR) technique was performed on alveolar lymphocytes recovered by BAL.

RESULTS

Analysis of the immunoglobulin heavy chain gene rearrangement showed a predominant clonal alveolar lymphocyte population in six of seven patients while all control subjects showed germline pattern.

CONCLUSIONS

Gene rearrangement analysis by PCR of alveolar lymphocytes would appear to be sensitive in patients with B-cell pulmonary NHL (six of seven patients) and specific (zero of nine in the control group). This simple test should be added only in the analysis of cells recovered by BAL in patients with suspected primary and secondary B-cell pulmonary NHL.

Gastric low-grade mucosa-associated lymphoid tissue lymphomas: their histogenesis and high-grade transformation

Gastric low-grade mucosa-associated lymphoid tissue (MALT) lymphoma is a unique disease. A vast majority of lymphoma cells are centrocyte-like cells or resemble monocytoid B cells, and occasionally show plasmacytic differentiation. Immunophenotypical and immunogenotypical examinations have indicated that they are in the differentiation stage of memory B cells, whose normal counterparts are marginal zone lymphocytes or monocytoid B cells in the lymphoid tissues. It arises from chronic gastritis closely associated with Helicobacter pylori (H. pylori) infection. Mucosa-associated lymphoid tissue lymphomas of other organs are also based on acquired MALT associated with chronic inflammation or autoimmune diseases. Interestingly, the majority of gastric low-grade MALT lymphomas regress by the eradication of H. pylori. The lymphoma cells, however, are not derived from B cells reacting with H. pylori itself but from autoreactive B cells. Although the mechanism of their oncogenesis has not been clarified, previous data suggest that autoreactive B cells proliferate in response to H. pylori-specific T cells, presumably with some cytokines. The genetic instability of such B cells then induces chromosomal abnormalities including trisomy 3 and/or other genetic changes. These B cells have the ability of autonomic proliferation and, even so, they might be sensitive to T cell stimuli. Low-grade gastric lymphomas occasionally progress to high-grade malignancy. The high-grade component of MALT lymphomas are composed of large-sized lymphoma cells that are morphologically indistinguishable from nodal large B cell lymphomas. This high-grade transformation is associated with p53 abnormalities or Bcl-6 overexpression. Gastric MALT lymphoma may provide a useful model in understanding multistep lymphomagenesis.

Molecular characterization of Warthin tumor

OBJECTIVE

Warthin tumor of the salivary gland is composed of oncocytic epithelium with a prominent follicular lymphoid infiltrate. The purpose of this study was to characterize the clonality of this lymphoid component by means of polymerase chain reaction technology.

STUDY DESIGN

DNA was isolated from paraffin-embedded tissue from 20 cases of typical Warthin tumor of the salivary gland and amplified by polymerase chain reaction to assess B- and T-cell clonality.

RESULTS

No dominant clonal populations were identified in any tumor. However, minor clonal expansions of both B and T cells were detected in up to 50% of tumors (immunoglobulin H, 50%; T-cell antigen receptor beta, 10%; T-cell antigen receptor gamma, 5%). No tumors showed evidence of bcl-2 proto-oncogene translocation, whereas 95% contained detectable Epstein-Barr virus DNA.

CONCLUSION

The B- and T-cell components of Warthin tumor are polyclonal with oligoclonal expansion of both T and B cells in some lesions.