High frequency of light chain restriction in labial gland biopsies of Sjögren's syndrome detected by in situ hybridization

Determination of light chain restriction in fine-needle aspiration-type preparations of B-cell lymphomas by mRNA in situ hybridization

The purpose of this study was to investigate whether B-cell clonality could be demonstrated in fine-needle aspiration (FNA)-type preparations by using automated and manual in situ hybridization (ISH) systems. FNA-like preparations were made from 10 cases of B-cell lymphoma and 5 cases of reactive lymphoid hyperplasia. Kappa/lambda expression was determined using an automated mRNA ISH assay or a manual ISH system. Other variables tested included type and length of fixation, protease digestion, and time in chromogen. Clonality data were corroborated by either flow cytometry or tissue-based analysis. Optimal conditions required formalin fixation, strong protease digestion, and prolonged hybridization and chromogen times; under these conditions, monoclonality was demonstrated by in situ in 8 of 10 cases. Each of the five cases of reactive lymphoid hyperplasia showed polyclonal light chain expression by automated mRNA ISH. In situ kappa/lambda mRNA analysis of FNA-type specimens allows direct determination of monoclonality in cytologic preparations.

Advanced diagnostic methods in oral and maxillofacial pathology. Part I: molecular methods

The practice of pathology is currently undergoing significant change, in large part due to advances in the analysis of DNA, RNA, and proteins in tissues. These advances have permitted improved biologic insights into many developmental, inflammatory, metabolic, infectious, and neoplastic diseases. Moreover, molecular analysis has also led to improvements in accuracy of disease diagnosis and classification. It is likely that, in the future, these methods will increasingly enter into the day-to-day diagnosis and management of patients. The pathologist will continue to play a fundamental role in diagnosis and will likely be in a pivotal position to guide the implementation and interpretation of these tests as they move from the research laboratory into diagnostic pathology. The purpose of this 2-part series is to provide an overview of the principles and applications of current molecular biologic and immunologic tests. Part I will discuss the biologic fundamentals of DNA, RNA, and proteins and the methods that are currently available or likely to become available to the pathologist in the next several years for their isolation and analysis in tissue biopsies.

Oral plasmablastic lymphoma in previously undiagnosed HIV disease

Non-Hodgkin's lymphoma is the second most common HIV-associated malignancy. This report details a case of the recently described entity plasmablastic lymphoma of the mouth in a patient who was later found to have severe HIV disease. The tumor manifested as a large ulcerated mass of the left maxillary alveolus, causing bony destruction and tooth mobility. Histologic examination of lesional tissue revealed a lymphoid tumor with a high proliferation rate containing lymphoplasmacytoid cells that were reactive to the plasma cell marker VS38c but not to CD20 or CD79a; these are features of the recently reported non-Hodgkin's lymphoma termed plasmablastic lymphoma. This is only the second report of an unusual tumor that has a predilection for the orofacial tissues.

Predictors of lymphoma development in primary Sjögren's syndrome

OBJECTIVE

To determine the clinical and laboratory predictors of lymphoma development in primary Sjögren's syndrome (pSS).

METHODS

Seventy-two patients with pSS were studied. Demographic data, clinical features, serum gamma-globulin levels, autoantibodies, and HLA status were reviewed. For statistical analysis, Mann-Whitney U-test, Fisher's exact test, logistic regression analysis, Kaplan-Meier method, and log-rank tests were applied.

RESULTS

Five patients developed a distinct non-Hodgkin's lymphoma of mucosa-associated lymphoid tissue (MALT). A history of swollen salivary glands, lymphadenopathy, and leg ulcers predicted lymphoma development.

CONCLUSION

Patients with pSS are at increased risk of lymphoma development, and those who have the above risk factors must be carefully observed.

[Gougerot-Sjögren syndrome and malignant lymphoproliferative syndromes]

INTRODUCTION

This review is aimed at defining the frequency, anatomical and clinical presentation, pathogenesis, predictive factors and treatment of malignant lymphoproliferative diseases occurring in the course of Sjögren's syndrome.

CURRENT KNOWLEDGE AND KEY POINTS

The frequency of non-Hodgkin's lymphoma (NHL) is estimated to be about 7%. Other malignant lymphoproliferative diseases (Waldenstrom's macroglobulinemia, multiple myeloma, Hodgkin's disease) are rarely observed. NHL is most frequently extranodal (affecting the salivary glands, stomach, lung, etc) in low grade malignancy (MALT lymphoma [mucosa associated lymphoid tissue]). The pathogenesis of NHL in Sjögren's syndrome is a multi-step process, including B cell monoclonal proliferation, oncogenic and/or infectious agents, and/or cytokines. Various predictive factors such as persistent enlargment of parotid glands, adenopathy, splenomegaly, mixed cryoglobulinemia, monoclonal gammopathy, suggest potential lymphoma evolution. The treatment of Sjögren's syndrome-associated NHL depends on the type of lymphoma. Moreover, in patients with low-grade lymphoma therapeutical strategies varies according to the stage and evolution of the disease.

FUTURE PROSPECTS AND PROJECTS

Future prospective longitudinal studies should permit to define the best criteria for malignant transformation and to improve therapeutical strategies.

Minor salivary gland hyalinisation and amyloidosis in low-grade lymphoma of MALT

Two patients with low-grade lymphoma of mucosa-associated lymphoid tissue (MALT) arising in primary Sjögren's syndrome developed solitary nodules in their lips. Histologically both lesions showed enlargement and hyalinisation of single minor salivary glands with acinar atrophy, loss of most ducts and conversion into almost acellular sclerotic eosinophilic masses. In one case the lesion was shown to contain an amyloid component. No amyloid was detected in the second case but deposition of collagen and basement membrane and sclerotic neoplasm were excluded.

Comparison of in situ hybridisation and polymerase chain reaction in the diagnosis of B cell lymphoma

AIM

To compare the sensitivity of the detection of immunoglobulin light chain messenger RNA (mRNA) restriction by in situ hybridisation (ISH) and clonal immunoglobulin heavy chain gene rearrangements by polymerase chain reaction (PCR) in the diagnosis of B cell lymphoma.

METHODS

Analyses were applied to formalin fixed, paraffin wax embedded, routine diagnostic specimens from cases with a provisional diagnosis of reactive lymph node (n = 23), B cell lymphoma (n = 21), and T cell lymphoma (n = 4). Nonisotopic ISH for kappa and lambda immunoglobulin light chain mRNA was performed using both fluorescein and digoxigenin labelled oligodeoxynucleotide probe cocktails. PCR was carried out on DNA extracted from sections using primers to framework 3 (Fr3) of the V segments and to conserved sequences from the J regions of the immunoglobulin heavy chain genes.

RESULTS

All reactive lymph nodes showed a polyclonal pattern of light chain mRNA by ISH, although one showed an excess of kappa positive cells. Nineteen of 21 (90%) cases of B cell lymphoma showed light chain restriction, and a further case showed a vast excess of kappa positive cells. By PCR, 20 of 23 reactive nodes (87%) showed a polyclonal pattern. In 13 of 21 B cell lymphomas (62%) a clonal band was detected.

CONCLUSION

In the diagnosis of B cell lymphoma in routinely processed diagnostic material ISH for light chain mRNA was more sensitive (90%) than PCR for heavy chain gene rearrangement using Fr3 and J region primers (62%).

Current concepts of autoimmune exocrinopathy: immunologic mechanisms in the salivary pathology of Sjögren's syndrome

Sjögren's syndrome is a systemic autoimmune disorder characterized by symptoms of oral and ocular dryness and a chronic, progressive loss of salivary and lacrimal function. The exocrine involvement is the result of a focal, peri-ductal mononuclear cell infiltrate and the subsequent loss of secretory epithelial cells. The mechanisms of this autoimmune exocrinopathy are not understood fully. Many recent investigations have described alterations in a number of immune mediators within the salivary glands. These studies provide new insights into the immune regulation of normal salivary gland functions and the mechanisms of gland damage in Sjögren's syndrome.

Lymphoma in Sjögren's syndrome. From histopathology to molecular pathology

A number of autoimmune diseases predispose to the development of neoplasia. A particularly well-recognized association is the development of lymphoma in Sjögren's syndrome. Although this risk has been estimated to be 44 times that of the general population, few reliable prognostic indexes exist for individual patients. Recent advances in molecular biology have improved our understanding of Sjögren's syndrome and permitted better characterization of the generalized lymphoproliferation associated with the condition. This article reviews the histopathology of the major and minor salivary gland lesions of Sjögren's syndrome and discusses advances in molecular biology that have permitted more accurate prediction of lymphoma development in this group of patients.

B-cell monoclonality in salivary lymphoepithelial lesions

It is well recognised that lymphoma may arise in a lymphoepithelial lesion of the salivary glands. Although the histological features of this lesion are well described, it is not clear what proportion contain monoclonal populations of lymphocytes at outset. In this study, 22 routinely processed lymphoepithelial lesions in parotid glands were examined for B-cell monoclonality using the polymerase chain reaction (PCR) to amplify the immunoglobulin heavy chain gene and using in situ hybridisation or immunohistochemistry to detect kappa or lambda light chain restriction. B-cell monoclonality was identified in 17/22 (77.3%) cases using a combination of the three methods. The detection rate for B-cell monoclonality was highest using PCR with 15/22 (68%) cases containing monoclonal immunoglobulin heavy chain gene rearrangements. In a proportion of cases the results of in situ hybridisation and immunohistochemistry were judged to be inadequate and this was probably a reflection of variations in fixation. In 7 patients, sequential biopsies were available from other sites and 6 of these also showed B-cell monoclonality. The results confirm the high prevalence of B-cell monoclonality in lymphoepithelial lesions of the major salivary glands. Furthermore, these results would suggest that PCR is a more reliable technique to identify B-cell monoclonality in routinely processed lymphoepithelial lesions compared to in situ hybridisation and immunohistochemistry.