A biomarker for lymphoma development in Sjogren's syndrome: Salivary gland focus score.

The aim of this study is to explore the role of labial minor salivary gland (LMSG) focus score (FS) in stratifying Sjögren's Syndrome (SS) patients, lymphoma development prediction and to facilitate early lymphoma diagnosis. Ιn an integrated cohort of 1997 patients, 618 patients with FS ≥ 1 and at least one-year elapsing time interval from SS diagnosis to lymphoma diagnosis or last follow up were identified. Clinical, laboratory and serological features were recorded. A data driven logistic regression model was applied to identify independent lymphoma associated risk factors. Furthermore, a FS threshold maximizing the difference of time interval from SS until lymphoma diagnosis between high and low FS lymphoma subgroups was investigated, to develop a follow up strategy for early lymphoma diagnosis. Of the 618 patients, 560 were non-lymphoma SS patients while the other 58 had SS and lymphoma. FS, cryoglobulinemia and salivary gland enlargement (SGE) were proven to be independent lymphoma associated risk factors. Lymphoma patients with FS ≥ 4 had a statistically significant shorter time interval from SS to lymphoma diagnosis, compared to those with FS < 4 (4 vs 9 years, respectively, p = 0,008). SS patients with FS ≥ 4 had more frequently B cell originated manifestations and lymphoma, while in patients with FS < 4, autoimmune thyroiditis was more prevalent. In the latter group SGE was the only lymphoma independent risk factor. A second LMSG biopsy is patients with a FS ≥ 4, 4 years after SS diagnosis and in those with FS < 4 and a history of SGE, at 9-years, may contribute to an early lymphoma diagnosis. Based on our results we conclude that LMSG FS, evaluated at the time of SS diagnosis, is an independent lymphoma associated risk factor and may serve as a predictive biomarker for the early diagnosis of SS-associated lymphomas.

Serum Helicobacter pylori antibody reactivity in seven Asian countries using an automated latex aggregation turbidity assay.

BACKGROUND AND AIM: To determine the application range of diagnostic kits utilizing anti-Helicobacter pylori antibody, we tested a newly developed latex aggregation turbidity assay (latex) and a conventional enzyme-linked immunosorbent assay (E-plate), both containing Japanese H. pylori protein lysates as antigens, using sera from seven Asian countries. METHODS: Serum samples (1797) were obtained, and standard H. pylori infection status and atrophy status were determined by culture and histology (immunohistochemistry) using gastric biopsy samples from the same individuals. The two tests (enzyme-linked immunosorbent assay and latex) were applied, and receiver operating characteristics analysis was performed. RESULTS: Area under the curve (AUC) from the receiver operating characteristic of E-plate and latex curves were almost the same and the highest in Vietnam. The latex AUC was slightly lower than the E-plate AUC in other countries, and the difference became statistically significant in Myanmar and then Bangladesh as the lowest. To consider past infection cases, atrophy was additionally evaluated. Most of the AUCs decreased using this atrophy-evaluated status; however, the difference between the two kits was not significant in each country, but the latex AUC was better using all samples. Practical cut-off values were 3.0 U/mL in the E-test and 3.5 U/mL in the latex test, to avoid missing gastric cancer patients to the greatest extent possible. CONCLUSIONS: The kits were applicable in all countries, but new kits using regional H. pylori strains are recommended for Myanmar and Bangladesh. Use of a cut-off value lower than the best cut-off value is essential for screening gastric cancer patients.

Risk adapted approach: How to treat splenic marginal zone lymphoma in resource-poor settings? - The real-life experience of a Brazilian cancer treatment center.

BACKGROUND: Splenic marginal zone lymphoma (SMZL) is a rare lymphoid B-cell malignant neoplasm with primary involvement of the spleen. It is a chronic disease, of indolent behavior and prolonged survival. However, 25% of cases have higher biological aggressiveness, propensity for histological transformation to high grade B-cell non-Hodgkin lymphoma and shortened survival. Recognition of these cases of reserved outcome is important for selecting a risk-adapted therapeutic approach in a resource-poor settings. METHODS: We described clinical and epidemiological characteristics, survival analysis and prognostic factors in a retrospective cohort of 39 SMZL patients, treated in Latin America. RESULTS: We observed a predominance of female (71.8%), median age of 63 years and higher incidence of B symptoms (56.4%) and extra-splenic involvement (87.1%) than in European and North-American series. With a median follow-up of 8.7 years (0.6-20.2 years), estimated 5-year overall survival (OS) and progression-free survival (PFS) were 76.9% and 63.7%, respectively. Factors with adverse prognostic impact on OS and PFS were Hb < 100 g/L, platelet count < 100 x 109/L, albumin < 3.5 g/dL, LDH > 480 U/L and high-risk Arcaini and SMZL/WG scores. Despite a relative low number of patients, no superiority was observed among the therapeutic regimens used including rituximab monotherapy, splenectomy and cytotoxic chemotherapy. CONCLUSION: Therefore, in resource-poor settings, where access to immunotherapy is not universal for all SMZL patients, we suggest that first-line should consist on rituximab therapy for elderly patients or with high surgical risk or with at least 1 risk factor identified in our study. Remainders can be safely managed with splenectomy.

Validation of the Marginal Zone Lymphoma International Prognostic Index.

The Marginal Zone Lymphoma International Prognostic Index (MALT-IPI) was recently developed for use in patients with mucosa-associated lymphoid tissue (MALT) lymphoma based on age, serum lactate dehydrogenase level, and Ann Arbor stage. In this study, we aimed to validate the MALT-IPI. A total of 455 MALT lymphoma patients were included in this study from between January 2005 and February 2017. Event-free survival (EFS), progression-free survival (PFS), cause-specific survival (CSS), and overall survival (OS) were the primary outcomes. Of the 455 patients, MALT-IPI low-, intermediate-, and high-risk groups included 309 (67.9%), 126 (27.7%), and 20 (4.4%) individuals, respectively. When comparing the low-risk group (L MALT-IPI) with the intermediate-high-risk group (I-H MALT-IPI), EFS, PFS, CSS, and OS were significantly different (p = 0.000, p = 0.000, p = 0.027, and p = 0.037). The International Prognostic Index and the Follicular Lymphoma International Prognostic Index failed to predict the prognosis of MALT lymphoma. Use of the MALT-IPI significantly differentiated L MALT-IPI from I-H MALT-IPI with respect to EFS, PFS, CSS, and OS. MALT-IPI is a valuable tool for the prediction of MALT lymphoma prognosis.

Short survival and frequent transformation in extranodal marginal zone lymphoma with multiple mucosal sites presentation.

Between 11 and 37% of extranodal marginal zone lymphoma (EMZL) patients present with disease involvement in multiple mucosal sites (MMS). We analyzed 405 EMZL patients seen between 1995 and 2017: 265 (65.4%) patients presented with stage I disease, 49 of 309 (15.8%) patients with bone marrow involvement, and 35 of 328 (10.7%) patients with monoclonal gammopathy (MG). Forty-three (10.6%) patients had MMS presentation, which was more frequently seen in patients aged >60 years (55.8%). Five (17.9%) of 28 MMS patients had MG. MMS patients commonly exhibited the International Prognostic Index (IPI) >2 (79.1%), Follicular Lymphoma International Prognostic Index (FLIPI) >2 (39.5%), and Mucosa-Associated Lymphoid Tissue Lymphoma International Prognostic Index (MALT-IPI) 2-3 (60.5%). Both MMS presentation and MG were associated with shorter survival univariately. In multivariable Cox regression models, shorter progression-free survival (PFS) and overall survival (OS) were observed in patients with MMS (hazard ratio [HR] = 3.08 and 2.92, respectively), age ≥60 years (HR = 1.52 and 2.45, respectively), and in patients who failed to attain a complete remission following initial therapy (HR = 3.27 and 2.13, respectively). Elevated lactate dehydrogenase was associated with shorter PFS (HR = 1.92), while anemia (HR = 2.46) was associated with shortened OS. MALT-IPI ≥2 (HR = 2.47 and 4.75), FLIPI >2 (HR = 1.65 and 2.09), and IPI >2 (HR = 2.09 and 1.73) were associated with shorter PFS and OS, respectively. Higher grade transformation (HGT) occurred in 11 (25.6%) MMS patients with a 5-year cumulative incidence of 13.2% (95% CI 4.7-26.1%). EMZL patients with MMS presentation represent a novel clinical subset associated with shorter PFS, OS, and higher incidence of HGT that needs novel therapeutic approaches.

Decreased Activity of Blood Acid Sphingomyelinase in the Course of Multiple Myeloma.

Acid sphingomyelinase (aSMase) is involved in the generation of metabolites that function as part of the sphingolipid signaling pathway. It catalyzes the breakdown of sphingomyelin into ceramide, a bioactive lipid that, among other roles, is involved in regulation of apoptosis. Dry drop blood test (DBS) and colorimetric 2-step enzymatic assay were used to assess the activity of human blood aSMase, beta-galactosidase, and beta-glucosidase, these enzymes are lysosomal hydrolases that catalyze the degradation of related sphingolipids, of sphingolipid signaling molecules. Blood was collected from a group of healthy volunteers and patients that were diagnosed with multiple myeloma (MM) in various stages of the disease. Additionally, activity of those enzymes in patients diagnosed with other hematological cancers was also assessed. We found that aSMase activity in the blood of patients with MM (at the time of diagnosis) was 305.43 pmol/spot*20 h, and this value was significantly lower (p < 0.030) compared to the healthy group 441.88 pmol/spot*20 h. Our collected data suggest a possible role of aSMase in pathogenesis of MM development.

Serum immunoglobulin free light chains are sensitive biomarkers for monitoring disease activity and treatment response in primary Sjögren's syndrome.

Objectives: Serum immunoglobulin free light chains (FLCs) are frequently elevated in B-cell-mediated autoimmune diseases, including primary SS (pSS). The objective of this study was to assess if serum FLCs can contribute to classification, mucosa-associated lymphoid tissue (MALT) lymphoma detection, monitoring of disease activity and treatment response in pSS. Methods: Serum samples of 100 consecutive patients suspected of pSS were included. Forty-five patients fulfilled ACR-EULAR criteria for pSS. Additionally, samples of 17 pSS patients with MALT lymphoma and longitudinal samples of pSS patients treated with rituximab (n = 20), placebo (n = 10) or abatacept (n = 15) were included. Serum FLCκ/FLCλ was measured by nephelometry or turbidimetry. Results: At diagnosis, FLCκ and FLCλ serum levels were significantly higher in pSS compared with non-SS sicca patients. The FLCκ/FLCλ ratio was abnormal in 11% of pSS patients. In established MALT-pSS patients, without recent rituximab treatment (n = 12), 50% had abnormal FLCκ/FLCλ ratios. FLC measurement had no additional value for pSS classification, compared with IgG and anti-SSA. FLC levels correlated significantly with systemic disease activity, assessed by EULAR SS Disease Activity Index (ESSDAI) and clinical ESSDAI, both cross-sectionally and longitudinally following treatment. Treatment with rituximab or abatacept significantly lowered FLC levels. FLCs show a large sensitivity to change and relative changes induced by treatment were higher compared with IgG. Conclusion: Serum FLCs are elevated in pSS, and abnormal FLCκ/FLCλ ratios may be indicative for the presence of MALT lymhoma. FLC levels can be used as a biomarker for systemic disease activity and monitoring treatment responses. FLCs are sensitive to change and have more favorable kinetics than IgG.

Intravenous immunoglobulin-induced acute thrombocytopenia.

BACKGROUND: Intravenous immunoglobulin (IVIG) has known efficacy in various hematologic conditions, including immune thrombocytopenic purpura. STUDY DESIGN AND METHODS: We present the clinical course of a patient with splenic marginal zone lymphoma, who developed acute thrombocytopenia on three consecutive episodes, with nadir counts of 27 × 109 , 50 × 109 , and 9 × 109 /L, upon administration of Intratect IVIG for hypogammaglobulinemia. An immunofluorescence test applying flow cytometry and monoclonal antibody immobilization of platelet antigens (MAIPA) assay were used to evaluate the reaction between IgG present in the IVIG preparations and the patient's or healthy donors' platelets (PLTs). RESULTS: A strong direct binding reaction was observed between the patient's PLTs and Intratect IgG using both methods. A similar reaction failed to materialize with controls. Binding was not antigen specific according to MAIPA. CONCLUSIONS: This is the first reported case of thrombocytopenia as a possible adverse effect of IVIG.

[MALT lymphoma accompanied by elevated serum IgM levels mimicking Waldenström's macroglobulinemia].

A 60-year-old man with chronic hepatitis C was referred to our hospital with significantly elevated total protein and serum IgM (9,500 mg/dl) levels identified via a routine checkup. Blood examination revealed increased serum IgM-monoclonal protein and serum-soluble IL-2 receptor (sIL2R) levels. Computed tomography and fluorodeoxyglucose positron emission tomography revealed pulmonary masses, abnormal soft tissue masses surrounding the bilateral kidneys, and thickened mucous membrane of the bladder with high fluorodeoxyglucose uptake. Pathological examination of the pulmonary mass revealed infiltration of medium-sized lymphocytes and plasma cells. Immunohistochemical analysis revealed tumor cells positive for CD138 and IgM, with a low positive rate of Ki-67 expression. Notably, the tumor cell-surrounding lymphocytes were positive for CD20. Although the patient was initially regarded as having Waldenström's macroglobulinemia owing to the significantly increased serum IgM levels, based on positive IgH-MALT1 translocation and negative MYD88 L265P mutation findings, he was further diagnosed with extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). Complete remission was achieved following six cycles of rituximab + CHOP therapy. This study data suggest that analysis of the MYD88 L265P mutation in tumor cells is suitable for accurately diagnosing hematopoietic malignancies with increased IgM monoclonal protein.

Pulmonary MALT Lymphoma in Patients with Sjögren's Syndrome.

To describe clinical features and outcomes of seven patients with pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma in the setting of underlying primary Sjögren's syndrome from a single center, we reviewed medical records of consecutive patients with pulmonary MALT lymphoma evaluated at our facility from January 1, 1999 to December 31, 2015 for clinical features, laboratory, pathologic and radiographic findings, management, and outcomes. Out of 13 patients with pulmonary MALT lymphoma, 7 (54 %) met the criteria for Sjögren's syndrome. The mean age at lymphoma diagnosis was 66 years; male-female ratio was 1:6. One-third of patients were asymptomatic at the time lymphoma was discovered. When symptomatic, patients reported nonspecific pulmonary complaints such as cough and dyspnea. All patients had positive antinuclear antibody and anti-SSA/Ro antibody. Rheumatoid factor was positive in six cases. A monoclonal gammopathy was present in three patients; the remaining four had polyclonal hypergammaglobulinemia. The radiologic, morphologic, and immunohistochemical features of primary Sjögren's syndrome-associated pulmonary MALT lymphomas did not differ significantly from pulmonary MALT lymphoma cases in general. All treatment modalities used resulted in complete and sustained response. One patient died 11 years after initial diagnosis with no lymphoma but of another cause. The remaining six patients are still alive and disease-free to date. The present series confirms the favorable course of pulmonary MALT lymphoma in Sjögren's patients. The overall imaging and pathologic features are in accordance with pulmonary MALT lymphoma not associated with primary Sjögren's syndrome. Further studies should be carried out in order to better understand pulmonary MALT lymphomagenesis, treatment, and outcomes in Sjögren's patients.

[Visceral leishmaniasis concurrent with splenic marginal zone B-cell lymphoma].

Splenic marginal zone B-cell lymphoma (SMZBCL) is a rare non-Hodgkin B-cell lymphoma that presents with morphologically mature lymphoid cells corresponding in their immunological characteristics to secondary follicular marginal zone lymphocytes. It is clinically characterized by splenomegaly, moderate lymphocytosis, usually focal bone marrow lesion, sometimes moderate of monoclonal immunoglobulin in the serum (generally IgM or IgG) and/or urea, and a relatively benign course. Leishmaniasis is a transmissible natural focal infectious endemic disease that has a great diversity of clinical manifestations. The authors describe Russia's first case of SMZBCL concurrent with visceral leishmaniasis in a 52-year-old female patient admitted to a hematology hospital with weakness, splenomegaly, and lymphadenopathy. The simultaneous detection of lymphoma and leishmaniasis in the same biopsy specimen is extremely rare. Visceral leishmaniasis should be borne in mind as an opportunistic infection in patients with malignancies, particularly in immunocompromised persons who live or have stayed in the endemic areas.

A case of marginal zone B cell lymphoma mimicking IgG4-related dacryoadenitis and sialoadenitis.

BACKGROUND: IgG4-related dacryoadenitis and sialoadenitis (IgG4-DS), so-called Mikulicz's disease, is characterized by elevated serum IgG4 and infiltration of IgG4-positive plasma cells in glandular tissues. Recently, several studies reported both malignant lymphoma developed on the background of IgG4-associated conditions and IgG4-producing malignant lymphoma (non-IgG4-related disease). CASE PRESENTATION: We report on the case of a 70-year-old man who was strongly suspected IgG4-DS because of high serum IgG4 concentration (215 mg/dl) and bilateral swelling of parotid and submandibular glands. Biopsies of cervical lymph node and a portion of submandibular gland were performed. These histopathological findings subsequently confirmed a diagnosis of marginal zone B cell lymphoma. CONCLUSION: Differential diagnosis of IgG4-DS is necessary from other disorders, including Sjögren's syndrome, sarcoidosis, Castleman's disease, Wegener's granulomatosis, lymphoma, and cancer. We suggest that biopsy of swollen lesions is important for a definitive diagnosis of IgG4-DS and discuss the mechanism of development in this case.

Transformation and additional malignancies are leading risk factors for an adverse course of disease in marginal zone lymphoma.

BACKGROUND: Marginal zone lymphoma (MZL) is a non-Hodgkin lymphoma that occurs as extra nodal, nodal, or splenic. While MZL is generally considered an indolent disease, a substantial percentage of patients follow an unfavorable course. The objective of this retrospective analysis was to identify predictors for a reduced overall survival (OS), or conversely an increased OS. PATIENTS AND METHODS: One hundred and ninety-seven MZL patients were analyzed. Apart from assessing previously published risk factors, concomitant morbidity at diagnosis, transformation into aggressive lymphoma, and occurrence of additional malignancies were evaluated. RESULTS: Next to the known risk factors, i.e. above 60 years of age and elevated serum lactate dehydrogenase (LDH), we demonstrate that transformation into aggressive lymphoma, as well as additional malignancies, are important independent risk factors for a shortened OS in a multivariate analysis, irrespective of the MZL localization. Impressively, in the group of patients lacking LDH elevation, transformation, and/or additional malignancies, only 1 of 63 patients died during follow-up compared with 37 of 87 patients in the high-risk group (HR = 22.8; 95% confidence interval 3.1-167.0; P = 0.002). CONCLUSIONS: Our analysis proposes novel risk factors and warrants for a continuous follow-up to detect the occurrence of transformation and additional malignancies early on.

Retrospective comparison of the effectiveness of various treatment modalities of extragastric MALT lymphoma: a single-center analysis.

We have performed a retrospective analysis of all patients with extragastric mucosa-associated lymphoid tissue (MALT) lymphoma treated at our institution to compare the efficacy of first-line therapeutic modalities including surgery, radiation, systemic therapy, and antibiotics. One hundred eighty-five patients with extragastric MALT lymphoma with a median age of 63 (interquartile range (IQR) 50-74) years and a median follow-up time of 49 (IQR 18-103) months were retrospectively analyzed. Time to progression and time to next therapy were used as surrogate endpoints for efficacy. Patients having either surgery (100 %), chemo/immunotherapy (85.5 %), or radiation (80 %) had significantly (p = 0.01) higher response rates than patients treated with antibiotics (33.3 %). Patients who were irradiated had significantly more progressive disease, but also the longest follow-up time. Stage, elevated LDH, anemia, elevated beta-2 microglobulin, plasmacytic differentiation, monoclonal gammopathy, or autoimmune disease did not influence the rate of disease progression nor did complete remission or partial remission from initial therapy influence time to and rate of progression. There was no significant difference in the median time to progression (p = 0.141), but the estimated time to progression (p = 0.023) as well as the estimated time to next therapy (p = 0.021) was significantly different among the various cohorts favoring surgery, chemo/immunotherapy, and radiation. Our results suggest extragastric MALT lymphoma as a potential systemic disease irrespective of initial stage. Radiation, surgery, and chemo/immunotherapy seem to be equally effective in achieving remissions and prolonged progression free survivals, but a curative potential is questionable. Localized MALT lymphomas affecting the thyroid gland or the lungs have excellent long-term progression-free survivals with surgical treatment only.

Risk stratification for Splenic Marginal Zone Lymphoma based on haemoglobin concentration, platelet count, high lactate dehydrogenase level and extrahilar lymphadenopathy: development and validation on 593 cases.

This international retrospective study of 593 Splenic Marginal Zone Lymphoma (SMZL) patients aimed to identify factors that determine treatment initiation and influence lymphoma-specific survival (LSS). Logistic regression was used to identify the factors associated with treatment. A Cox regression was used to analyse LSS in a derivation cohort of 366 patients. This produced a prognostic index (PI) and enabled the identification of three risk groups. The resulting stratification was validated in another cohort of 227 patients and compared with the Interguppo Italiano Linfomi (IIL) score in the group of 450 patients for whom all the required data were available using an extension of the net reclassification improvement. Haemoglobin concentration (Hb), extrahilar lymphadenopathy and hepatitis C virus status were associated with the initiation of treatment. Hb, platelet count, high lactate dehydrogenase level and extrahilar lymphadenopathy were independently associated with LSS. Three risk groups with significantly different five-year LSS (94%, 78% and 69%, respectively) were identified. This stratification (named HPLL on the basis of determinant factors) had a better discriminative power than the IIL score. This system is useful for stratifying SMZL patients into risk groups and may help in the selection of risk-tailored treatment approaches.

First-line therapy with doxycycline in ocular adnexal mucosa-associated lymphoid tissue lymphoma: a retrospective analysis of clinical predictors.

This retrospective study was launched to evaluate the efficacy of doxycycline and to find independent predictors of a clinical response in patients with ocular adnexal lymphoma of mucosa-associated lymphoid tissue (OAML). Thirty-eight patients with newly diagnosed, localized OAML received doxycycline for 3 weeks (12 patients) or 6 weeks (26 patients). Clinical factors including absolute lymphocyte count (ALC) and neutrophil count (ANC) were compared between responders and non-responders. After a median follow-up of 26.4 months, doxycycline resulted in an overall response rate of 47% and a 3-year time-to-treatment failure (TTF) rate of 84%. Patients treated with doxycycline for 6 weeks versus 3 weeks tended to have a higher response rate (54%vs 33%). Absolute lymphocytosis (ALC > 3.01 x 10(9)/L) and absolute neutrophilia (ANC > 1.92 x 10(9)/L) were defined based on the median value of each count. Patients with (19 patients) versus without absolute lymphocytosis had significantly shorter 2-year TTF (70%vs 100%, P = 0.021) and a lower response rate (32%vs 63%, P = 0.051). Absolute lymphocytosis (odds ratio [OR] = 4.7; 95% confidence interval [CI], 1.1-20.8; P = 0.043) and non-conjunctival tumor (OR = 11.8; 95% CI, 1.1-122.5; P = 0.038) were negative predictors for response by multivariate analysis. Front-line doxycycline is effective particularly in localized OAML patients without absolute lymphocytosis but with conjunctival involvement.

Mucosa-associated lymphoid tissue lymphoma of the appendix vermiformis.

A 60-year-old woman with right lower abdominal pain was admitted to our hospital. Computed tomography demonstrated right hydronephrosis and an irregular mass of 4 x 3 cm adjacent to the ileocecal region and iliopsoas muscle. Preoperative serum soluble anti-interleukin-2 receptor antibody was elevated (689 U/ml). Laparotomy showed an appendiceal tumor invading the cecum, mesocolon, right ureter, and duodenum. Right hemicolectomy with partial resection of the right ureter was performed. Histologic examination revealed diffuse infiltration of centrocyte-like cells, scattered plasma cells, and immunoblasts. The centrocyte-like cells were immunohistochemically positive for CD20 and CD79a, and were negative for BCL2, CD3, CD5, and CD10; this was compatible with primary mucosa-associated lymphoid tissue (MALT) lymphoma. The patient has shown a favorable course without recurrence for 2 years postoperatively. This is the sixth documented case of primary MALT lymphoma of the appendix. The spectrum of sites in which gastrointestinal MALT lymphomas occur should be expanded to include the appendix.

[MALT B cell lymphoma with kidney damage and monoclonal gammopathy: a case study and literature review]. / Linfoma de células B tipo MALT con afectación renal y gammapatía monoclonal: presentación de un caso y revisión de la literatura.

We report a case of low-grade B-cell lymphoma of mucosa-associated lymphoid tissue (MALT) involving the left kidney and simultaneous onset of a monoclonal gammopathy IgM kappa. No predisposing local inflammatory condition was identified. Following left nephrectomy, the renal specimen showed the centrocyte like cells and lymphoid cells in the lymphoepithelial lesions were positive for CD20 and CD79α. The neoplastic cells expressed monotypic cytoplasmic IgM kappa. The demonstration of bone marrow cells of B-lineage expressing the same monoclonal protein as the tumor suggested bone marrow involvement, even in the absence of identical morphology. Despite chemotherapy and rituximab treatment, clinical follow-up showed right kidney extension with high-grade transformation, and finally systemic dissemination. This case illustrates that the kidney is among the sites that may be involved by MALT B-cell lymphomas in a primary or secondary fashion, and the need for expanded investigation of the possible dissemination. We review the literature on this unusual extranodal lymphoma.