Primary malignant lymphoma of the salivary gland: a tumor of mucosa-associated lymphoid tissue

Lymphoma of the Sublingual Gland: Clinical, Morphological, Histopathological, and Genetic Characterization

Background: Lymphoma of the sublingual gland is rare, representing 1% of all salivary gland lymphomas. In this case report, we present three new cases and compare them to previously published cases, with the aim of characterizing the clinical, morphological, histopathological, and genetic features of this type of malignancy.

Materials and Methods: We provide a clinical description of three cases along with a characterization of the microscopic features, including morphology, and immunohistochemistry. In addition, we analysed possible cytogenetic rearrangements with the use of fluorescence in situ hybridization (FISH).

Results: Case 1: A 61-year-old male presenting with a painless swelling of the floor of the mouth diagnosed as extranodal marginal zone lymphoma (EMZL) of the left sublingual gland. The patient is alive with no evidence of disease after his fourth treatment regimen following several relapses. Case 2: A 68-year-old female with a prior history of mantle cell lymphoma (MCL) presenting with a tender swelling of the left sublingual gland as well as the right submandibular gland. The lesions were diagnosed as relapsing MCL. The patient died of unrelated causes after 18 months of treatment. Case 3: A 75-year-old female presenting with a swelling of the floor of the mouth diagnosed as follicular lymphoma (FL) of the left sublingual gland. The patient received chemotherapy along with radiotherapy and was still alive 10 years after the diagnosis.

Conclusion: The three cases of sublingual gland lymphomas presented in this case report resemble lymphomas of other major salivary glands. The clinician should be aware of this type of malignancy and that the clinical presentation may not differ from benign lesions or other more common malignancies in this location.

Sjögren Syndrome in Primary Salivary Gland Lymphoma

OBJECTIVES

Sjögren syndrome (SS) is considered as a major etiologic factor for primary salivary gland lymphoma (SGL). However, the percentage of SGL that is caused by SS (and thus the real impact of SS on SGL epidemiology) is unclear. We aimed to assess the prevalence of SS in patients with SGL through a systematic review and meta-analysis.

METHODS

Electronic databases were searched for studies assessing the presence of SS in patients with SGL. Pooled prevalence of SS in SGL was calculated, with a subgroup analysis based on histotype (mucosa-associated lymphoid tissue [MALT] vs non-MALT).

RESULTS

Sixteen studies with 665 SGLs were included. Pooled prevalence of SS in SGL was 18.2%, with high heterogeneity among studies. In MALT SGL, the prevalence of SS was 29.5%, with moderate heterogeneity. In non-MALT SGL, the prevalence of SS was 0%, with null heterogeneity.

CONCLUSIONS

SS seems to be responsible for a significant but minor portion of SGLs. SS appears involved in MALT-type SGL but not in other histotypes.

Oral manifestations of lymphoma: a systematic review

Lymphoma is a malignant disease with two forms: Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). Non-Hodgkin's lymphoma is diagnosed in extranodal sites in 40% of cases, and the head and neck region is the second most affected, with an incidence of 11-33%, while HL has a very low incidence in extranodal sites (1-4%). The aim of this study was to identify the oral manifestations of lymphoma through a systematic literature review, which we conducted using the PubMed, Lilacs, Embase, and Cochrane Library databases. We found 1456 articles, from which we selected 73. Among the intraoral findings, the most frequent were ulcerations, pain, swelling, and tooth mobility, while the extraoral findings included facial asymmetry and cervical, submandibular, and submental lymphadenopathy. Among the few studies reporting imaging findings, the most cited lesions included hypodense lesions with diffuse boundaries, bone resorptions, and tooth displacements. The publications reviewed highlight gaps in the areas of early detection, diagnosis, and proper treatment.

An Algorithm Approach to Diagnosing Bilateral Parotid Enlargement

Objective

This contemporary review aims to categorize the disease entities that cause bilateral parotid enlargement and to develop a question-based algorithm to improve diagnosis of bilateral parotid masses.

Data Sources

A PubMed search for bilateral and parotid showed 818 results. Of these, 68 relevant studies were reviewed to compile a list of disease processes that can cause bilateral parotid enlargement.

Review Methods

A total of 22 diseases entities were reviewed. The disease processes were initially grouped into 6 categories based on etiology: sialadenosis, infection, neoplasm, autoimmune, iatrogenic, and miscellaneous. For each lesion, the incidence, history, and physical examination were compiled in a matrix.

Conclusion

After reviewing the matrix, it was clear that grouping diseases based on specific history and physical findings limits the differential diagnosis. The most important factors included disease incidence, timing of onset, nodular or diffuse, pain, and overlying skin changes. With this algorithm, the differential diagnosis can be limited from 28 to 7 or fewer likely diagnoses for a given presentation.

Implications for Practice

Bilateral parotid disease has a wide differential diagnosis with an expanding number of available tests. An algorithm, based solely on data obtained from the history and physical examination in the first patient encounter, may reduce the differential and aid the clinician in deciding on further workup and treatment. Following the algorithm presented here should allow the clinician to arrive at a diagnosis rapidly without ordering unnecessary tests and wasting resources.

[MALT lymphoma of the parotid salivary gland]

BACKGROUND

Mucosa-associated lymphoid tissue (MALT) lymphoma was described for the first time in 1983 by Isaacson and Wright. It was classified into extranodal non-Hodkin's lymphomas of B-cell lymphocytes of the marginal zone of reactive lymphe follicles. It is characterized by both hyperplasia and colonization of plasmocytic, centrocytoid and monocytoid cells, by the infiltration of interfollicular and parafollicular parts of interstitium, as well as by the invasion of clusters of neoplastic lymphoid cells of the glandular epithelium, forming the pathognomic lymphoepithelial MALT limphoma lesions.

CASE REPORT

In this paper we presented the two female patients, 59 and 75 years of age, with MALT lymphomas, associated with Miculicz's and Sjögren's syndromes. The paper also underlined rather many-month-long, indolent clinical course, evalution of both tumors, massive in size, as well as two-sided localization in the case of the Miculicz's syndrome. After the subtotal parotidectomy, using conservation of nerve facialis, the tissue blocks were fixed in 10% formaldehyde. The paraffine sections were stained by routine histochemical and an immunohistochemical method by using monoclonal antibodies for both B-cell and T-cell lymphomas, due to the verification of lymphoepithelial lesions. The MALT lymphoma diagnosis was based on the histological criteria and confirmed by an immunohistochemical method. After the surgical therapy accompanied by chemotherapy, the patients were controlled at regular intervals, and residual MALT lymphoma did not appear.

CONCLUSION

MALT lymphoma is a rare tumor of the salivary glands, with the most frequent localization in the parotide gland. It had a slow clinical course, without metastases in both patients. The diagnosis was made pathohistologically and confirmed immunohistochemically. The surgical therapy was accompained by adjuvant chemotherapy.

Most cases of primary salivary mucosa-associated lymphoid tissue lymphoma are associated either with Sjoegren syndrome or hepatitis C virus infection

Salivary gland mucosa-associated lymphoid tissue (MALT) lymphomas (SGML) are rare, as are data concerning their behaviour. We analysed clinical features at presentation, particularly the association with Sjoegren syndrome (SS) and hepatitis C virus (HCV) infection, and outcome in 33 cases of SGML diagnosed between March 1985 and April 2003. There were five males and 28 females, with a median age of 61 years. At presentation, 12/33 (36%) had multiple salivary glands or mucosal involvement and four had bone marrow infiltration. Ann Arbor stage was IE in 15 (46%), IIE in four (12%) and IV in 14 patients (42%). Fifteen patients had a history of SS (46%), two of other autoimmune diseases, seven of HCV infection. No case had both SS and HCV. Of the 29 treated patients, 17 received surgery or local radiotherapy; 69% achieved complete remission. Histological transformation occurred in four (12%). Five patients died (three of lymphoma, two of unrelated causes). The 5 year-overall survival (OS), cause-specific survival and progression-free survival was 85 +/- 8%, 94 +/- 6% and 65 +/- 10% respectively. Overall, the disease course was indolent, despite the advanced stage at diagnosis, and local therapy often appeared to be adequate. The only prognostic factors influencing OS were histological transformation and age. The close association of SGML with either autoimmune diseases or HCV infection in our series (73%) confirms their possible role in the pathogenesis of these lymphomas.

Diagnosis of intra-oral MALT lymphoma using seminested polymerase chain reaction

Diagnosis of mucosa-associated lymphoid tissue (MALT) lymphoma based on histological examination alone is difficult. We report three patients with histologically suspected MALT lymphoma who developed lymphoproliferative lesions of the sublingual gland. Seminested polymerase chain reaction (PCR) analysis applied to formalin-fixed and paraffin-embedded specimens showed clonal rearrangement of immunoglobulin heavy chain genes in two patients and a polyclonal characteristic in one. The clinical findings and Southern blot analysis confirmed the accuracy of the diagnosis. The molecular method described can be applied routinely to processed specimens to obtain helpful information for the diagnosis of low-grade malignancies of lymphoproliferative disorders, such as MALT lymphoma.

Hodgkin and non-Hodgkin lymphoma of the head and neck: clinical, pathologic, and imaging evaluation

Lymphomas are subdivided into HL and NHL and are more specifically classified into subtypes of HL or NHL according to the WHO classification. HLs involve the lymph nodes predominantly and only approximately 5% arise in extranodal sites, whereas 30% of NHLs present in extranodal sites. Imaging studies, including CT and MR imaging, cannot distinguish [figure: see text] HL from NHL, and cannot differentiate their various subtypes, necessitating a pathologic diagnosis. Clinical parameters, however, can be helpful in differentiating the two broad categories of lymphomas, and subtypes of lymphomas have predilections for different sites within the head and neck. HL is most commonly located in the lymph nodes of the neck and mediastinum. Marginal-zone lymphoma has an affinity for the ocular adnexa, salivary glands, larynx, and the thyroid gland. Diffuse large B-cell lymphoma is commonly encountered in the paranasal sinuses, mandible, maxilla, and Waldeyer ring. Burkitt lymphoma occurs more frequently in children and young adults and frequently affects the maxilla and mandible, with a greater distribution of involvement at a lower frequency. On imaging studies, the lymph nodes of HL and NHL are homogeneous and variable in size, with an average diameter from 2 to 10 cm. They may enhance slightly to moderately, display necrosis before and after treatment, and display calcification post-treatment. NHL in extranodal sites in the head and neck (nasopharynx, Waldeyer ring, oral cavity, and larynx) manifests frequently as a submucosal mass accompanied [figure: see text] by polypoid, bulky masses with a smooth mucosal surface. Clinically aggressive lymphomas, such as Burkitt lymphoma, diffuse large B-cell lymphoma, and NK-/T-cell lymphomas are characterized by destruction of the maxilla, mandible, and bones around the paranasal sinuses, which is indistinguishable from bony destruction in other malignant tumors, such as SCC. Contrast CT is indicated for evaluation of cervical lymph nodes; the chest, including the mediastinum; the pelvic cavity; paranasal sinuses; and orbits. CT is also useful for detection of bone destruction involving the base of the skull, paranasal sinuses, and the mandible or maxilla. MR imaging is preferred for the assessment of extension of lymphomas to different fascial spaces (parapharyngeal, masticator, infratemporal fossa, tongue, and nasopharynx) and for intracranial extension. Lymphomas are isodense to muscle on CT and circumscribed with distinct margins that occasionally display extranodal extension with less-well-defined margins and areas of necrosis within the tumor matrix. Lymphomas appear low in signal intensity on T1-weighted images and low to high in signal intensity on T2-weighted images, with variable, but usually low, enhancement following introduction of Gadolinium-DTPA (Gd-DTPA) contrast material.

Detection of the apoptosis-suppressing oncoprotein bcl-2 in salivary gland lymphoma

The bcl-2 proto-oncogene encodes an inner mitochondrial membrane protein that blocks apoptosis and programmed cell death in human lymphoid tissue. In this study a monospecific anti-human bcl-2 antibody that is reactive in formalin-fixed tissues was used with an avidin-biotin complex immunoperoxidase method to evaluate 41 cases of lymphoproliferative disorders of the salivary gland. The study cases were 26 primary salivary gland lymphomas (including 21 B-cell lymphomas four T-cell lymphomas and one true histiocytic lymphoma) and 15 cases of myoepithelial sialadenitis. Bcl-2 expression is restricted to the mantle zone and interfollicular lymphocytes around reactive germinal centers of myoepithelial sialadenitis. Seventeen of the 21 B-cell lymphomas were positive for bcl-2, and were composed of mucosa-associated lymphoid tissue (MALT), centrocytic, centroblastic-centrocytic and centroblastic lymphomas. Noticeably, all 11 cases of MALT lymphoma were bcl-2 positive. In contrast, staining for bcl-2 was present in only one of four cases of T-cell lymphomas and was negative in one true histiocytic lymphoma. The expression of bcl-2 protein was also investigated in the ductal systems and epimyoepithelial islands of salivary glands from patients with malignant lymphoma and myoepithelial sialadenitis. While salivary ducts in eight of 15 cases of myoepithelial sialadenitis immunostained for bcl-2, epimyoepithelial islands showed bcl-2 expression in only five cases of myoepithelial sialadenitis. We found that ductal cells in the salivary gland from patients with primary non-Hodgkin's lymphomas expressed bcl-2 protein. It was of interest that epimyoepithelial islands in all cases of MALT lymphoma displayed bcl-2 expression whereas other subtypes of B-cell lymphoma, T-cell lymphoma and true histiocytic lymphoma were invariably negative. These results indicate that bcl-2 is expressed in a wide variety of non-Hodgkin's lymphomas, especially when all 11 cases of MALT lymphoma are bcl-2 positive. Epimyoepithelial islands in MALT lymphoma express this oncoprotein, and their ability to induce bcl-2 synthesis resulted in the prevention of apoptosis and prolonged cell survival. Furthermore, the expression of bcl-2 protein in the lymphoma cells may be responsible for the induction of bcl-2 expression in the adjacent epimyoepithelial islands through a lymphocyte chemical mediator.

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.

Malignant lymphoma of the mandible: report of a case

Extranodal malignant lymphoma is relatively rare. When it occurs in the oral region, it is sometimes misdiagnosed as inflammatory disease. This report details a case of malignant lymphoma that involved the fight mandibular region.

Expression of bcl-2 oncogene product in primary non-Hodgkin's malignant lymphoma of the oral cavity

The B-cell leukemia/lymphoma-2 (bcl-2) proto-oncogene is peculiar, as its product appears to provide survival advantage to B cells by blocking apoptosis. Expression of bcl-2 protein was analyzed in 54 cases of primary non-Hodgkin's malignant lymphomas of the oral cavity by immunohistologic staining of paraffin-embedded tissue. The immunophenotype of each tumor was established with the use of a panel of monoclonal and polyclonal antibodies to lymphoid cell differentiation antigens. The cases in the present study were 42 B-cell lymphomas, 7 T-cell lymphomas and 5-lymphomas revealing histiocytic markers. Sixteen of the 42 B-cell lymphomas were positive for bcl-2 protein, and were composed of 7 low-grade B-cell lymphomas and 9 high-grade B-cell lymphomas. Seven low-grade B-cell lymphomas were composed of one mucosa-associated lymphoid tissue type, three centrocytic types and three centroblastic-centrocytic types. Nine high-grade B-cell lymphomas comprised four centroblastic types, one immunoblastic type and four lymphoblastic types. Enhanced expression of the bcl-2 oncogenic protein was detectable in lymphoma cells in 2 cases for the T-cell lymphoma, and one case for the true histiocytic lymphoma. In contrast to the previous reports of American node-based lymphomas, Japanese primary oral lymphomas in our series expressed a lower frequency of bcl-2 protein. Furthermore, the present study indicated that bcl-2 protein was expressed on a wide variety of B-cell lymphomas, T-cell lymphomas and true histiocytic lymphoma, and that differences in bcl-2 protein expression may be useful in the diagnostic separation of lymphoblastic lymphoma with B-cell marker from Burkitt's lymphoma.

Immunoglobulin gene rearrangements in lymphoplasmacytic infiltrates of labial salivary glands in Sjögren's syndrome. A possible predictor of lymphoma development

OBJECTIVES

Sjögren's syndrome is an autoimmune disorder in which patients have a well-recognized risk of developing malignant lymphoma. Although some clinical parameters may herald the onset of lymphoma, few reliable histologic or molecular markers are available that predict progression to a malignant lymphoproliferative disorder. The purpose of this study was to identify the prevalence of immunoglobulin heavy chain monoclonality in labial gland biopsies of patients with Sjögren's syndrome and to compare this to clinical outcome.

STUDY DESIGN

The polymerase chain reaction was applied to 76 sequential labial salivary gland biopsies from patients under investigation for Sjögren's syndrome. A seminested polymerase chain reaction technique was used on DNA extracted from formalin-fixed, paraffin-embedded tissue to amplify the V-D-J region of the immunoglobulin heavy chain gene. Thirty-four randomly selected labial salivary glands that showed nonspecific sialadenitis from patients without Sjögren's syndrome were used as controls.

RESULTS

Monoclonality, as defined by a single band on polyacrylamide gel electrophoresis was detected in 11 cases (14.5%). Of cases that showed monoclonality, four patients were subsequently diagnosed with extrasalivary lymphoma. In each case the rearranged bands in the lip biopsy and the lymphoma were the same size. In one patient who later developed lymphoma, a monoclonal rearranged immunoglobulin band was not identified. In addition, no cases of the translocation t(14;18) were identified by polymerase chain reaction in any of the lip biopsies showing heavy chain monoclonality or in any of the extrasalivary gland lymphomas.

CONCLUSIONS

These results suggest that monoclonal immunoglobulin heavy chain gene rearrangements are a relatively common finding in patients with Sjögren's syndrome and may prove to be a useful marker for predicting the progression to, and early detection of malignant lymphoma.