Gastric MALT lymphoma of low-grade malignancy. Apropos of 4 surgically treated cases

From 1990 to 1993, programmed surgery was performed in four patients with histologically low grade malignant gastric lymphomas of mucosa-associated lymphoid tissue (MALT) (partial gastrectomy = 1, total gastrectomy = 3). These small cell lymphomas have the B phenotype and are uncommon. The clinical course is usually slow and classically limited to the stomach. As for other gastric lymphomas, there is still a certain amount of discussion as to the best therapeutic choice between surgery, chemotherapy and radiotherapy. Certain elements in the literature can help in managing these low grade gastric lymphomas. Recent publications report on a prospective study on primary lymphomas of the digestive tract, a clinical trial on single drug chemotherapy alone and the relationships between Helicobacter pylori and MALT lymphoma.     

A clinicopathologic study of primary gastric lymphoma of B-cell type among the Japanese with special reference to low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT)

The most common primary site of low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) is the gastrointestinal tract, particularly the stomach. The relationship of MALT lymphomas, however, with the more commonly occurring large B-cell gastric lymphoma has not been directly discussed except in the report of Chan et al. (1990), which lacked clinical information regarding the behavior of these tumors. To elucidate the relationship between high-grade large-cell lymphoma and MALT lymphoma, we studied in detail the histopathological and clinicopathologic features with the survival date of 77 Japanese cases of primary gastric lymphoma (PGL) of B-cell type. Based on degree of morphologically recognizable low- or high-grade components of the tumor, PGL was divided into four types: 18 cases of pure MALT lymphoma (type I); 13 cases of MALT lymphoma with small area of high-grade lymphoma (type II); 22 cases of high-grade lymphoma with small areas of MALT lymphoma (type III); and 24 cases pure high-grade lymphoma (type IV). Corresponding to the differences in the histologic pictures of each type, there were differences in the gross appearance, pathologic stage (including depth of invasion) and prognosis. These data suggests that both MALT and high-grade lymphomas of the stomach belong to the same cell lineage and constitute a pathological spectrum and that the histological grouping of PGL is clinico-pathologically useful.     

Ocular adnexal lymphoma. A clinicopathologic study with identification of lymphomas of mucosa-associated lymphoid tissue type

PURPOSE: Extranodal marginal zone B-cell lymphoma (low-grade B-cell lymphoma of mucosa-associated lymphoid tissue [MALT] type) is a distinctive type of lymphoma that usually arises in association with mucosa or other epithelial structures and has an indolent clinical course. The frequency and clinical features of MALT lymphomas in the ocular adnexa have not been well studied. METHODS: The authors examined the clinicopathologic features of ocular adnexal lymphoma, identified a subset of cases with MALT characteristics, and determined patient outcome. RESULTS: The 42 patients, 16 men and 26 women age 35-89 years (mean, 64) were followed an average of 4.8 years. Thirty-two patients had ocular adnexal involvement at presentation (primary ocular adnexal lymphoma) and 10 had a history of lymphoma that relapsed in the orbit (secondary ocular adnexal lymphoma). In the primary group, 23 patients had lymphoma confined to the ocular adnexa, 3 had a single lesion that invaded adjacent structures, and 6 had distant spread at the time of presentation. Twenty-five patients achieved a complete remission. Nine patients, including 6 patients whose disease was localized initially, had progression or relapse of disease in distant sites. At last follow-up, 21 patients were free of disease, 9 were alive with disease and 2 had died of lymphoma. In the secondary group, at last follow-up, 1 patient had died of other causes, free of lymphoma, 3 patients were alive with disease and 5 had died of lymphoma (outcome not known in 1 case). Using the recently described revised European-American lymphoma classification, we found 16 MALT lymphomas, 8 diffuse large B cell, 12 follicular center, 3 mantle cell, 1 B-small lymphocytic lymphoma, and 2 unclassifiable low-grade lymphomas. The most common type of primary lymphoma was MALT type (15 of 30 classifiable cases), and the most common secondary lymphoma was follicular center (6 of 10). No increased frequency of conjunctival or lacrimal gland involvement by MALT lymphomas was found. All 33 lymphomas with immunophenotyping were of B lineage. CONCLUSIONS: Ocular adnexal lymphomas are B-cell tumors that develop in older adults, predominantly among women. Primary orbital lymphomas have a favorable prognosis; a high proportion of them have MALT characteristics.     

Seasonal rhythm of red pigment concentrating hormone in the crayfish

To evaluate the significance of microsatellite instability (MI) and loss of heterozygosity (LOH) in the development of gastric lymphoma, we examined 33 tissue-samples of 20 primary gastric B-cell lymphomas (6 low-grade lymphomas of mucosa-associated lymphoid tissue [MALT; 10 samples] and 14 diffuse large B-cell lymphomas [23 samples]). MI and LOH were evaluated at 13 microsatellite loci. In MALT lymphoma, four of six cases showed MI at one to two microsatellite loci (average 1.0 per case, 0.8 per sample), whereas in diffuse B-cell lymphoma, all samples showed MI at one to five microsatellite loci (average 2.4 per case, 2.7 per sample) (p < 0.05 and p = 0.0001). MI at the c-myc gene locus was most frequent in both types of gastric lymphomas (3 of 6 and 11 of 14 cases, respectively). Regional heterogeneity of the MI pattern was observed in two of four cases of MALT lymphoma and in four of five cases of diffuse B-cell lymphoma. On the other hand, LOH was observed only in one MALT lymphoma and in three diffuse B-cell lymphomas. Genetic instability may be an important mechanism for the development and progression of gastric lymphoma. Frequent MI at the c-myc locus might reflect an activated state and the importance of this gene in mucosal lymphocytes of chronic gastritis.     

Gastrointestinal lymphomas: an overview with emphasis on new findings and diagnostic problems

The first section of this article summarizes the salient clinicopathologic features of the more common types of primary gastrointestinal lymphomas, the recent explosion of information on the low grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT), and new findings on multiple lymphomatous polyposis and ulcerative jejunitis. The second section discusses the practical problems that may be encountered in the diagnosis of gastrointestinal lymphomas, including diagnosis of large cell malignancies, distinction between lymphoma and reactive lymphoid hyperplasia, classification of diffuse small B-cell lymphomas (including the potential pitfall of mistaking Burkitt's lymphoma for small B-cell lymphoma), recognition of large cell transformation in low-grade B-cell MALT lymphoma, assessment of gastric biopsies from MALT lymphoma patients after anti-Helicobacter therapy, and assessment of nodal or splenic involvement in low-grade MALT lymphoma.     

An unusual case of primary leptomeningeal marginal zone B-cell lymphoma

Primary leptomeningeal lymphomas are rare, and usually follow a rapid clinical course with early systemic involvement. A 60-year-old woman presented with a 3-year history of worsening seizures and memory loss. Neuroimaging showed widespread meningeal calcification. After extensive investigations a meningeal biopsy revealed a low-grade B-cell lymphoma categorized as an extranodal marginal zone B-cell lymphoma, attributed to the same histological group as the MALT (mucosa-associated lymphoid tissue) lymphomas described in the stomach, thyroid, salivary glands and orbit. There was no evidence of systemic involvement. The extensive meningeal calcification would appear to be a novel finding in primary leptomeningeal lymphoma whereas the unusually long clinical history in this case is possibly related to the particular histological type of low-grade B-cell lymphoma.     

Primary cutaneous large B-cell lymphomas of the legs. A distinct type of cutaneous B-cell lymphoma with an intermediate prognosis. Dutch Cutaneous Lymphoma Working Group

BACKGROUND AND DESIGN: Primary cutaneous follicular center cell lymphomas represent a distinct type of cutaneous B-cell lymphoma, clinically characterized by localized skin lesions on the head or trunk and an excellent prognosis. Histologically similar lymphomas may occur on the legs. The clinical behavior of this group is still undefined, and controversy exists whether these lymphomas should be classified as follicular center cell lymphoma or B-immunoblastic lymphoma. We reviewed the clinical, histologic, and follow-up data of 18 patients with primary cutaneous large B-cell lymphoma of the legs. RESULTS: Primary cutaneous large B-cell lymphoma of the legs generally occurred in elderly patients (median age at diagnosis, 76 years), in particular women (male-female ratio, 7:2), and preferentially affected the lower legs (14 of 18 patients). Radiotherapy and/or systemic polychemotherapy resulted in complete remissions in 16 of 17 patients. Follow-up data demonstrated estimated 2- and 5-year survival rates of 77% and 58%, respectively. Histologic evaluation showed diffuse dermal infiltrates with variable proportions of centroblasts (large noncleaved cells), large centrocytes (large cleaved cells), and B immunoblasts. Seventeen of 18 patients were diagnosed as having primary cutaneous follicular center cell lymphoma; only 1 patient, whose histologic examination showed more than 30% immunoblasts, was diagnosed as having B-immunoblastic lymphoma. CONCLUSIONS: Primary cutaneous large B-cell lymphoma of the legs is a distinct clinicopathologic entity that mainly affects elderly patients and has an intermediate prognosis. Although most cases have a follicular center cell origin, primary cutaneous large B-cell lymphoma is proposed as the most appropriate term for this type of cutaneous lymphoma.     

Non-Hodgkin's lymphoma of the thyroid: a retrospective review of all patients diagnosed in Nottinghamshire from 1973 to 1992

The pathological and clinical features were reviewed of all primary non-Hodgkin's lymphomas (NHL) of the thyroid gland diagnosed between 1973 and 1992 in the population (1.1 million) served by the Nottingham and North Nottinghamshire Health Authorities. Of the 43 patients with histologically proven NHL, three had low grade mucosa associated lymphoid tissue (MALT) lymphomas (Stage IEA, 2; Stage IIEA, 1), 35 had intermediate or high grade lymphomas, Stage IEA or IIEA (intermediate MALT, 2; high grade MALT, 14; B-cell diffuse centroblastic, 17; anaplastic large cell (Ki-1) of null cell type, 1; high grade unclassifiable, 1), and one had unclassifiable NHL Stage IIEA. One patient had Stage IIIEA disease (high grade MALT) and three had stage IVA disease (high grade MALT, 2; B-cell diffuse centroblastic, 1). The median age was 68 years (range 45-86) with a female: male ratio of 6:1. For the 35 patients with intermediate or high grade thyroid NHL (Stages IEA and IIEA) the 5- and 10-year cause specific survival was 60%. The 21 patients treated between 1985 and 1992 initially with chemotherapy (except stage IEA (< 5 cm diameter) had a 5-year cause specific survival of 69% (95% CI 48-90) compared with 46% (95% CI 19-73) for the 14 patients treated between 1973 and 1984 with initial radiotherapy (Chi 2 = 1.62). The survival of those patients with intermediate or high grade MALT lymphomas was not significantly greater than of those patients with B-cell diffuse centroblastic NHL.     

Uncommon clinical presentation of a lymphocytic lymphoma of intermediate differentiation in a patient with systemic sclerosis

The association of systemic sclerosis (SSc) and non-Hodgkin lymphoma is a rare event and its pathogenetic mechanism remains to be clarified. We describe a previously unreported association of SSc with a lymphocytic lymphoma of intermediate differentiation (IDL), involving the gastrointestinal tract, gallbladder and one salivary gland. Whereas the morphological, immunological and cytogenetic features were typical of IDL, the extensive extranodal involvement and the association with an autoimmune disorder were suggestive of two other lymphomas of mantle lineage: mucosa-associated lymphoid tissue (MALT) lymphoma and monocytoid B-cell lymphoma (MBCL).     

Antigen-dependent progression of mucosa-associated lymphoid tissue (MALT)-type lymphoma in the stomach. Effects of antimicrobial therapy on gastric MALT lymphoma in mice

In humans, low-grade B-cell mucosa-associated lymphoid tissue (MALT) lymphomas of the stomach regress when Helicobacter pylori infection is cured by antimicrobial therapy. Using an animal model of human gastric MALT lymphoma, we observed the effects of Helicobacter felis eradication and the relationship between infection and disease progression. Antimicrobial therapy was given to one-half of the BALB/c mice infected with H. felis for 20 months. Groups of antibiotic-treated and untreated mice were killed 2, 3, and 4 months after antimicrobial therapy (ie, 22, 23, and 24 months after infection). The numbers of mice with MALT decreased after H. felis eradication with no lymphoid follicles seen 4 months after treatment. MALT lymphoma was present in a total of 23% (11/48) of antibiotic-treated infected mice compared with 75% (27/36) in untreated infected mice. These lymphomas were further graded into low-, intermediate-, and high-grade lymphoma. In the untreated mice, lymphoma development was more advanced with 36% low-grade (13/36), 39% intermediate-grade (14/36), and 6% high-grade (large B-cell) lymphoma (2/36) whereas in the treated mice the incidence was 21% (10/48), 6% (3/48), and 0% (0/48), respectively. These observations suggest that antigenic stimulation by H. felis sustained growth and progression of low-grade MALT lymphoma and that primary high-grade gastric lymphomas can evolve from the transformation of these tumors. Eradication of the organism caused low-grade tumors to regress, with inhibition or slowing down of lymphoma development toward high-grade lymphoma. The H. felis mouse model of gastric MALT lymphoma presents an opportunity to address the issues arising from antimicrobial treatment of these tumors in humans.     

Biased VH family usage in primary gastric B cell lymphoma of mucosa-associated lymphoid tissue-type and the selected V beta expression of T cells infiltrating into the lymphoma cells

Seven cases of primary gastric low-grade B cell lymphoma of mucosa-associated lymphoid tissue (MALT) type, two cases of high-grade B cell lymphoma with a low-grade component and three cases of pure high-grade lymphoma were selected for the current study. The Ig VH gene use of lymphoma cells and the V beta repertoires of infiltrating T cells were investigated. The VH gene analysis showed multiple VH family usage in 12 cases, but the MALT-type lymphoma cell usage was found to be biased for the families that have a low number of VH genes (VHIV and V). Another analysis of lymphoma-infiltrating T cells showed restricted expressions of the V beta repertoire in all seven low-grade cases and three high-grade cases. In those 10 cases, a considerable number of CD4-positive T cells infiltrated into lymphoma cells and RAG-1 was also prominently expressed. Based on these findings, it was thus assumed that the normal counterpart of gastric B cell lymphoma of MALT type is different from the conventional B cell lymphoma, and the restricted expression of V beta repertoires is therefore considered to be a characteristic finding in low-grade B cell lymphomas of MALT type as well as in a proportion of high-grade lymphomas (the so called 'high-grade lymphoma of MALT type').     

Evaluation of CD23 expression in paraffin-embedded gastric lymphomas of mucosa-associated lymphoid tissue

The CD23 antigen is expressed in a normal subset of B lymphocytes and in some non-Hodgkin's lymphomas. Reactivity for anti-CD23 (BU38) is present in paraffin-embedded tissue in the large majority of nodal small lymphocytic lymphomas, as well as in follicular center cell lymphomas. Most studies of gastric lymphomas of mucosa-associated lymphoid tissue (MALT) reported a lack of CD23, but these studies were performed on frozen tissue. We evaluated CD23 staining in paraffin-embedded tissue in a large series of gastric MALT lymphomas, as well as in cases of chronic gastritis. We assayed 49 well-characterized gastric lymphomas (9 high-grade non-MALT and 40 MALT [20 low grade, 13 mixed low and high grade, and 7 high grade]). High-grade MALT lymphomas without a low-grade component were distinguished from high-grade non-MALT lymphomas by the presence of lymphoepithelial lesions composed of large cells. In addition, we studies nine cases of chronic gastritis containing B-cell aggregates. We used anti-CD23 (BU38) in formalin-fixed, paraffin-embedded tissue. All of our low-grade gastric MALT lymphomas lacked CD23 immunoreactivity. One of the 13 mixed low-grade and high-grade lesions showed CD23 expression in the high-grade component. All of the high-grade MALT and high-grade non-MALT lesions lacked CD23. All of the nine cases of chronic gastritis lacked CD23. CD23 highlighted residual follicular dendritic cells and gastric epithelium. We concluded that gastric MALT lymphomas lacked CD23 (BU38) in paraffin-embedded tissue, with rare exceptions. This lack of CD23 expression might represent a useful feature in small or partially crushed biopsy specimens, particularly in the differential diagnosis with follicular small cleaved cell lymphoma presenting in the gastrointestinal tract.     

Ongoing somatic mutations and clonal expansions after cure of Helicobacter pylori infection in gastric mucosa-associated lymphoid tissue B-cell lymphoma

PURPOSE: Although most patients with primary gastric low-grade mucosa-associated lymphoid tissue (MALT) B-cell lymphoma experience complete endoscopic and histologic remission after the cure of Helicobacter pylori infection, in many patients, the polymerase chain reaction (PCR) still detects monoclonal B cells in the gastric mucosa. The present study asked whether the lymphoma immunoglobulin VH (IgVH) sequences remained stable in patients with gastric MALT lymphoma after H pylori eradication. PATIENTS AND METHODS: Eight patients with stage EI disease treated with H pylori eradication were analyzed before and at different time points after the cure of the infection. After the amplification of IgVH genes from DNA extracted from gastric biopsy specimens, monoclonal PCR products were cloned and multiple clones (43 to 105) were sequenced per patient. RESULTS: Mutations were detected in all lymphoma VH sequences, which suggested germinal center or postgerminal center origin of the lymphoma B cells. In five of the eight patients, clonal heterogeneity was observed at diagnosis or during follow-up. Genealogical analysis of shared and unshared mutations showed that the process of somatic mutations was ongoing after H pylori eradication in four of the five patients who showed clonal instability. Ongoing mutations were observed in three of the four patients who completely responded to H pylori eradication, but in only one of the four patients who did not respond or who partially responded. CONCLUSION: In low-grade gastric MALT lymphomas, an ongoing process of somatic hypermutation and antigen selection can be detected after the therapeutic removal of the underlying stimulus H pylori. These data point to the relevance of yet unknown antigens that drive this disease. In addition, they challenge the view that these lymphomas may be cured solely by the eradication of H pylori.     

Effects of maternal exercise on fetal activity in late gestation

Sixty malignant non-Hodgkin's lymphomas originating in the upper aerodigestive tract have been analyzed for their cytologic type, immunophenotype and association with the Epstein-Barr virus (EBV). The majority of these tumors were B-cell lymphomas of blastic cytology (78%) with the exception of lymphomas in the parotid gland. Large B-cell lymphomas were the most frequent encountered in the sinonasal region and Waldeyer's ring. Twelve lymphomas were of T- or T/NK (natural killer)-cell lineage. They were in the nasal cavity and the paranasal sinuses (4), the tonsil (5), and the oral cavity (3). Epstein-Barr sequences were detected in five angiocentric T/NK-lymphomas, one peripheral T-cell lymphoma, one lymphoma of lymphomatoid granulomatosis type, one large B-cell lymphoma, and in a lymphoroliferative disorder in an HIV-positive patient. These results suggest that EBV is not involved in lymphomagenesis of B-cell tumors, but is associated with angiocentric T/NK-cell lymphoma in the upper aerodigestive tract.     

The t(11;18)(q21;q21) chromosome translocation is a frequent and specific aberration in low-grade but not high-grade malignant non-Hodgkin's lymphomas of the mucosa-associated lymphoid tissue (MALT-) type

Primary extranodal malignant non-Hodgkin's lymphoma arising from the mucosa-associated lymphoid tissue (MALT-type lymphoma) represents a subtype of B-cell lymphoid malignancies with distinct clinicopathological features and is often associated with a favorable prognosis. Unlike the situation in nodal non-Hodgkin's lymphoma of B-cell lineage, few data are still available concerning the chromosomal constitution of MALT-type lymphomas. Until now, cytogenetic data from 29 low-grade MALT lymphomas with karyotypic alterations have been reported from different institutions, and virtually no data were available for high-grade MALT-type lymphomas. We have analyzed the cytogenetics of 44 MALT lymphomas arising in the stomach, parotid gland, thyroid gland, lung, breast, and conjunctiva. Clonal chromosome aberrations have been detected in 13 of 20 (65%) low-grade and 20 of 24 (83%) high-grade tumors. More than half of the low-grade lymphomas with abnormal karyotypes (7 of 13 cases, 53%) displayed clonal t(11;18)(q21;q21), thus specifically associating this translocation with MALT-type lymphomas for the first time in a larger series. In contrast, t(11;18) was not found in a single case of 20 high-grade MALT-type lymphomas with abnormal karyotypes, nor were translocations t(14;18) or t(3;14), characterizing about 10-35% of primary nodal large cell lymphomas. Instead, these lymphomas were associated with t(8;14)(q24;q32) in three cases, frequent deletions in the long arm of chromosome 6, and partial or whole gains of chromosomes 3, 7, 17, 18, and 21.     

Primary cardiac lymphoma. No evidence for an etiologic association with Epstein-Barr virus

OBJECTIVES: To report two cases of primary cardiac lymphoma, a rare extranodal lymphoma with an unknown pathogenesis, and to compare them to secondary B-cell cardiac lymphoma. DESIGN: Clinicopathologic features are described, using histologic and immunophenotypic examinations. The Epstein-Barr virus genome is detected by in situ hybridization. PATIENTS: Of 80 autopsied cases of malignant lymphoma identified at Nagoya (Japan) University Hospital, two patients with primary cardiac lymphoma and five patients with secondary cardiac B-cell lymphoma were selected. RESULTS: None of the seven selected cases showed immunodeficiency, autoimmune disorders, or chronic inflammatory processes. Primary cardiac lymphomas had B-cell phenotypes with mu and lambda chain monoclonality. Immunostaining for Epstein-Barr virus (latent membrane protein-1) and Epstein-Barr virus-encoded RNA-1 in situ hybridization did not demonstrate an association of these lymphoma with Epstein-Barr virus infection. The majority of secondary cardiac B-cell lymphomas were extranodal lymphomas and extranodal or serosal involvement was more prominent than nodal involvement. CONCLUSION: These findings suggest that primary cardiac lymphoma, unlike pyothorax-associated pleural lymphoma, appears to have no association with chronic inflammation or Epstein-Barr virus infection.     

Intramedullary localization of a primary cerebral lymphoma in AIDS

A 36 years-old male with AIDS, presented with left hemiparesis revealing a right parietal tumour. Stereotactic biopsy demonstrated a malignant non-Hodgkin's lymphoma. His condition partially improved following radiotherapy and chemotherapy. Three months later he was re-admitted with progressive bilateral root pain and urinary incontinence resulting in paraplegia with sensory loss below T10. He died one month later from generalized sepsis. Neuropathology confirmed an immunoblastic B-cell malignant non-Hodgkin's lymphoma in the white matter of the right parietal lobe and revealed a centrospinal localisation of the lymphoma in the thoracic cord at T10. There was no visceral localisation of the tumour. Secondary spread to the spinal cord of malignant non Hodgkin's lymphomas, usually causes meningo-myelo-radiculitis. Intraspinal deposits of primary cerebral lymphomas are uncommon and have never been previously described in AIDS, to our knowledge. Their pathogenesis is unclear. In our case, neuropathological findings are consistent with diffusion of the primary tumour to leptomeninges and secondary infiltration of the spinal cord along the perivascular spaces.     

Marginal zone B-cell lymphomas including mucosa-associated lymphoid tissue type lymphoma (MALT), monocytoid B-cell lymphoma and splenic marginal zone cell lymphoma and their relation to the reactive marginal zone

The marginal zone of the B follicle represents a well-defined compartment of the B area. Its cellular composition is distinct from that of the follicle centre, from which it also differs in its functional role in the immune response. Several newly identified lymphoma entities, e.g. extranodal MALT type lymphoma, nodal monocytoid B-cell lymphoma and splenic marginal zone B-cell lymphoma, display in common a very peculiar organoid growth pattern reminiscent of the marginal zone. Moreover, their neoplastic components share morphologic and phenotypic similarities to the cellular components of the marginal zone. The clinical characteristics of these various marginal zone cell lymphomas may differ depending of the organ which is involved. Nevertheless, they all share common cytogenetic abnormalities suggesting a common pathogenesis.     

Characteristic pattern of chromosomal gains and losses in primary large B-cell lymphomas of the gastrointestinal tract

In contrast to low-grade B-cell lymphomas originating in the gastrointestinal (GI) tract, only few cytogenetic data are available for the large cell, highly malignant variants. We studied 31 large B-cell lymphomas of the GI tract by comparative genomic hybridization (CGH) and fluorescence in situ hybridization using specific DNA probes (FISH). The most frequent aberrations were gains of all or of parts of chromosomes 11 (11 cases), 12 (9 cases), 1q (4 cases), and 3q (4 cases). Losses of parts of chromosome 6q and of parts of the short arm of chromosome 17 (6 cases each) were found most frequently. In four cases a total of seven high-level DNA amplifications was detected. In two of these cases, involvement of specific protooncogenes (REL and MYC) was shown. Some genetic aberrations seemed to be associated with an inferior clinical course: patients with >/=2 aberrations had a significantly shorter median survival. Furthermore, all patients with gains of all or parts of chromosome arm 1q and with high-level DNA amplifications as well as seven of nine patients with gains of all or parts of chromosome 12 died of lymphoma. In conclusion, the pattern of chromosomal gains and losses in large B-cell lymphomas was different from data reported for low-grade (MALT) lymphomas of the stomach and bowel, especially with respect to the high incidence of partial gains of chromosome arm 11q and of all or parts of chromosome 12 and the low frequency of polysomy 3. In addition, our data suggest that chromosomal gains and losses detected by CGH and FISH may predict for the outcome of patients with this tumor entity.     

Malignant lymphoma of mucosa-associated lymphoid tissue in the larynx

A 36-year-old woman was referred to the department of Otolaryngology/Head and Neck Surgery, University Hospital Vrije Universiteit, because of complaints of hoarseness. A submucosal swelling of the right ventricular fold was found that was subsequently biopsied. Histopathological examination showed a low-grade B-cell non-Hodgkin's lymphoma of mucosa-associated lymphoid tissue (MALT). Treatment consisted of local radiotherapy (to 2800 cGy). During the 2-year follow-up to date there has been no evidence of recurrent disease. To our knowledge, only four cases of MALT lymphomas in the larynx have been reported. The clinical behavior of MALT lymphoma is clearly quite distinct and requires proper recognition to prevent inadvertent misdiagnosis of overtreatment.