Guiding function of positron emission tomographycomputed tomography examination in the diagnosis and treatment of ocular adnexal mucosa associated lymphoid tissue lymphoma

AIM:To explore the role of positron emission tomographycomputed tomography(PET-CT)examination in the diagnosis and treatment of ocular adnexal mucosa associated lymphoid tissue lymphoma(OAML).METHODS:The general clinical data,postoperative PET-CT results,treatment regimens,and the prognosis of 21 histopathologically confirmed OAML patients between October 2017 and September 2021 were collected.Among the 21 patients,five patients underwent surgical treatment alone,13 patients underwent surgical treatment combined with radiotherapy,and three patients underwent surgical treatment combined with chemotherapy.RESULTS:The follow-up period ranged from 8 to 79mo,with four cases of recurrence and no deaths.Through PETCT examination,two patients exhibited both local ocular metabolic elevation and systemic metastasis,and one of these patients had cervical lymph node metastasis,while the other had submandibular and parotid gland metastasis.Nine patients showed only local ocular metabolic elevation,while 10 patients had no abnormal metabolic activity locally.CONCLUSION:PET-CT examination plays a crucial role in detecting residual lesions and recurrence following tumor resection,aiding in precise disease staging,and facilitating the development of personalized treatment plans,ultimately improving patient prognosis.

Colonic adenocarcinoma,mucosa associated lymphoid tissue lymphoma and tuberculosis in a segment of colon:A case report

Synchronous occurrence of adenocarcinoma and mucosa associated lymphoid tissue(MALT) lymphoma of colon is rare,and its presence with coexisting tuberculosis is still rarer.To our knowledge,this may be the first case report.In the present report,we describe a 43-year-old female who presented with a history of abdominal pain,fever,loss of weight and loss of appetite.Colonoscopy showed a large ulceroproliferative mass arising from the caecum,biopsy of which showed it to be adenocarcinoma of the colon.A right hemicolectomy was performed and microscopic study of the colon revealed tuberculosis and synchronous adenocarcinoma with lymphoma.Eight of sixteen lymph nodes showed tuberculosis and three of sixteenpericoloniclymphnodes showed metastatic deposits.Immunostains further confirmed the tumour to be adenocarcinoma with MALT lymphoma.We would like to highlight the diagnostic challenges arising from the multi-faceted presentations of these three conditions.

Helicobacter pylori infection in gastric mucosa-associated lymphoid tissue lymphoma

Gastrointestinal lymphoma is the most common type of extranodal lymphoma,and most commonly affects the stomach.Marginal zone B-cell lymphoma of the mucosa-associated lymphoid tissue(MALT)and diffuse large B-cell lymphoma are the most common histologic types of gastric lymphoma.Despite its increasing incidence,diagnosis of gastric lymphoma is difficult at an earlier stage due to its nonspecific symptoms and endoscopic findings,and,thus,a high index of suspicion,and multiple,deep,repeated biopsies at abnormally and normally appearing sites in the stomach are needed.In addition,testing for Helicobacter pylori(H.pylori)infection and endoscopic ultrasonography to determine the depth of tumor invasion and involvement of regional lymph nodes is essential for predicting response to H.pylori eradication and for assessment of disease progression.In addition,H.pylori infection and MALT lymphoma development are associated,and complete regression of low-grade MALT lymphomas after H.pylori eradication has been demonstrated.Radiotherapy and/or chemotherapy can be used in cases that show poor response to H.pylori eradication,negativity for H.pylori infection,or high-grade lymphoma.

Role of Helicobacter pylori virulence factor cytotoxin-associated gene A in gastric mucosa-associated lymphoid tissue lymphoma

Helicobacter pylori(H.pylori)infection might initiate and contribute to the progression of lymphoma from gastric mucosa-associated lymphoid tissue(MALT).Increasing evidence shows that eradication of H.pylori with antibiotic therapy can lead to regression of gastric MALT lymphoma and can result in a 10-year sustained remission.The eradication of H.pylori is the standard care for patients with gastric MALT lymphoma.Cytotoxin-associated gene A(CagA)protein,one of the most extensively studied H.pylori virulence factors,is strongly associated with the gastric MALT lymphoma.CagA possesses polymorphisms according to its C-terminal structure and displays different functions among areas and races.After being translocated into B lymphocytes via typeⅣsecretion system,CagA deregulates intracellular signaling pathways in both tyrosine phosphorylation-dependent and-independent manners and/or some other pathways,and thereby promotes lymphomagenesis.A variety of proteins including p53and protein tyrosine phosphatases-2 are involved in the malignant transformation induced by CagA.Mucosal inflammation is the foundational mechanism underlying the occurrence and development of gastric MALT lymphoma.

Helicobacter pylori and gastric mucosa-associated lymphoid tissue lymphoma:Recent progress in pathogenesis and management

Recent progress in the research regarding the molecular pathogenesis and management of gastric mucosaassociated lymphoid tissue(MALT)lymphoma is reviewed.In approximately 90%of cases,Helicobacter pylori(H.pylori)infection plays the causative role in the pathogenesis,and H.pylori eradication is nowadays the first-line treatment for this disease,which leads to complete disease remission in 50%-90%of cases.In H.pylori-dependent cases,microbe-generated immune responses,including interaction between B and T cells involving CD40 and CD40L co-stimulatory molecules,are considered to induce the development of MALT lymphoma.In H.pylori-independent cases,activation of the nuclear factor-κB pathway by oncogenic products of specific chromosomal translocations such as t(11;18)/API2-MALT1,or inactivation of tumor necrosis factor alpha-induced protein 3(A20)are considered to contribute to the lymphomagenesis.Recently,a largescale Japanese multicenter study confirmed that the long-term clinical outcome of gastric MALT lymphoma after H.pylori eradication is excellent.Treatment modalities for patients not responding to H.pylori eradication include a"watch and wait"strategy,radiotherapy,chemotherapy,rituximab immunotherapy,and a combination of these.Because of the indolent behavior of MALT lymphoma,second-line treatment should be tailored in consideration of the clinical stage and extent of the disease in each patient.

Helicobacter pylori-negative gastric mucosa-associated lymphoid tissue lymphomas: A review

Since Isaacson and Wright first reported on the extranodal marginal zone B-cell lymphoma of the stomach in 1983,following studies have clarified many aspects of this disease.We now know that the stomach is the most affected organ by this disease,and approximately90% of gastric mucosa-associated lymphoid tissue(MALT) lymphomas are related to Helicobacter pylori(H.pylori) infection.This implies that approximately 10% of gastric MALT lymphomas occur independent of H.pylori infection.The pathogenesis of these H.pylori-negative gastric MALT lymphomas remains unclear.To date,there have been several speculations.One possibility is that genetic alterations result in nuclear factor-kappa B(NF-κB) activation.Among these alterations,t(11;18)(q21;q21) is more frequently observed in H.pylori-negative gastric MALT lymphomas,and such translocation results in the synthesis of fusion protein API2-MALT1,which causes canonical and noncanonical NF-κB activation.Another possibility is infection with bacteria other than H.pylori.This could explain why H.pylori eradication therapy can cure some proportions of H.pylori-negative gastric MALT lymphoma patients,although the bacteria responsible for MALT lymphomagenesis are yet to be defined.Recent advances in endoscopy suggest magnifying endoscopy with narrow band imaging as a useful tool for both detecting gastric MALT lymphoma lesions and judging the response to treatment.A certain proportion of H.pylori-negative gastric MALT lymphoma patients respond to eradication therapy; hence,H.pylori eradication therapy could be considered as a first-line treatment for gastric MALT lymphomas regardless of their H.pylori infection status.

Primary thymic mucosa-associated lymphoid tissue lymphoma with multiple thin walled lung cysts: case report and literature review

Mucosa-associated lymphoid tissue （MALT） lymphoma of the thymus is rare. We reported a case of a 37-year-old Chinese female with Sjtgren＇s syndrome and hyperglobulinemia. She suffered from chronic cough for 3 weeks. Chest computed tomography （CT） demonstrated a multiloculated cystic mass in mediastinum prevascular space and multiple lung cysts. Laboratory exam of autoimmune markers showed positive of antinuclear antibody （ANA）, Sjtgren＇s syndrome A （SSA）, Sjtgren＇s syndrome B （SSB）, and rheumatoid factors （RF）. Thymectomy with lymph node dissection was performed. The pathology report revealed thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue. Under immunohistochemical stains, CD20 and Bcl-2 were positive. No evidence of recurrence of disease was found.

Gastric low-grade mucosal-associated lymphoid tissue-lymphoma: Helicobacter pylori and beyond

The stomach is the most frequently involved site for extranodal lymphomas,accounting for nearly two-thirds of all gastrointestinal cases.It is widely accepted that gastric B-cell,low-grade mucosal-associated lymphoid tissue(MALT)-lymphoma is caused by Helicobacter pylori(H.pylori)infection.MALT-lymphomas may engender different clinical and endoscopic patterns.Often,diagnosis is confirmed in patients with only vague dyspeptic symptoms and without macroscopic lesions on gastric mucosa.H.pylori eradication leads to lymphoma remission in a large number of patients when treatment occurs at an early stage(Ⅰ-Ⅱ1).Neoplasia confined to the submucosa,localized in the antral region of the stomach,and without API2-MALT1 translocation,shows a high probability of remission following H.pylori eradication.When both bacterial infection and lymphoma recur,further eradication therapy is generally effective.Radiotherapy,chemotherapy and,in selected cases,surgery are the available therapeutic options with a high success rate for those patients who fail to achieve remission,while data on immunotherapy with monoclonal antibodies (rituximab)are still scarce.The 5-year survival rate is higher than 90%,but careful,long-term follow-up is required in these patients since lymphoma recurrence has been reported in some cases.

Gastric mucosa-associated lymphoid tissue lymphomas and Helicobacter pylori infection:A Colombian perspective

AIM:To assess the significance of chromosome translocation t(11;18)(q21;q21),B-cell lymphoma 10 (BCL-10) protein and Helicobacter pylori (H.pylori) infection in gastric mucosa-associated lymphoid tissue (MALT) lymphoma in Colombia.METHODS:Fifty cases of gastric MALT lymphoma and their respective post-treatment follow-up biopsies were examined to assess the presence of the translocation t(11;18)(q21;q21) as identified by fluorescence in situ hybridization;to detect protein expression patterns of BCL10 using immunohistochemistry;and for evaluation of tumor histology to determine the correlation of these factors and resistance to H.pylori eradication.RESULTS:Infection with H.pylori was confirmed in all cases of gastric MALT lymphoma in association with chronic gastritis.Bacterial eradication led to tumor regression in 66% of cases.The translocation t(11;18)(q21;q21) was not present in any of these cases,nor was there evidence of tumor transformation to diffuse large B-cell lymphoma.Thirty-four percent of the patients showed resistance to tumor regression,and within this group,7 cases,representing 14% of all those analyzed,were considered to be t(11;18)(q21;q21)-positive gastric MALT lymphomas.Protein expression of BCL10 in the nucleus was associated with the presence of translocation and treatment resistance.Cases that were considered unresponsive to therapy were histologically characterized by the presence of homogeneous tumor cells and a lack of plasmacytic differentiation.Responder cases exhibited higher cellular heterogeneity and a greater frequency of plasma cells.CONCLUSION:Both t(11;18)(q21;q21)-positive MALT lymphoma cases and those with nuclear BCL10 expression are considered resistant to H.pylori eradication.It is suggested that chronic antigenic stimulation is not a dominant event in resistant cases.

Primary mucosa-associated lymphoid tissue lymphoma of the liver: A report of two cases and review of the literature

Mucosa-associated lymphoid tissue(MALT) lymphoma of the liver is a very rare condition and thus the diag-nosis may be challeng-ing-. The clinical presentation is usually variable, rang-ing- from minimal clinical symptoms to severe end stag-e liver disease. In this paper, we describe the clinicopatholog-ic finding-s in two cases of primary hepatic MALT lymphoma. One case is an 80-year-old female with no underlying- chronic liver disease and the second case is a 30-year-old female with autoimmune hepatitis complicated by MALT lymphoma. In both specimens, there was diffuse infiltration of atypical B-lymphocytes that were positive for CD20 and CD79 a, but neg-ative for CD5, CD43 and CD10. There were occasional lymphoepithelial lesions involving- the hepatocytes or bile ducts. Polymerase chain reaction analysis showed monoclonal immunog-lobulin heavy chain g-ene rearrang-ement in both cases. The first case was treated with surg-ery but developed pulmonary recurrence a year after complete resection but went into remission following- treatment with rituximab. A second recurrence occurred in the rig-ht parotid g-land 7 years later, which was treated with idelalisib. The second case was effectively treated with rituximab. To our knowledg-e, the second case is the first reported case linked to autoimmune hepatitis.

Role of Helicobacter pylori in gastric mucosa-associated lymphoid tissue lymphomas

Mucosa-associated lymphoid tissue(MALT)lymphoma is an indolent extranodal marginal zone B-cell lymphoma,originating in acquired MALT that is induced in mucosal barriers as part of a normal adaptive immune response to a chronic immunoinflammatory stimulus,most notably chronic infection by Helicobacter pylori(H.pylori).This antigenic stimulation initially leads to lymphoid hyperplasia;the acquisition of additional genetic aberrations culminates in the activation of intracellular survival pathways,with disease progression due to proliferation and resistance to apoptosis,and the emergence of a malignant clone.There are descriptions of MALT lymphomas affecting practically every organ and system,with a marked geographic variability partially attributable to the epidemiology of the underlying risk factors;nevertheless,the digestive system(and predominantly the stomach)is the most frequently involved location,reflecting the gastrointestinal tract’s unique characteristics of contact with foreign antigens,high mucosal permeability,large extension and intrinsic lymphoid system.While early-stage gastric MALT lymphoma can frequently regress after the therapeutic reversal of the chronic immune stimulus through antibiotic eradication of H.pylori infection,the presence of immortalizing genetic abnormalities,of advanced disease or of eradication-refractoriness requires a more aggressive approach which is,presently,not consensual.The fact that MALT lymphomas are rare neoplasms,with a worldwide incidence of 1-1.5 cases per105population,per year,limits the ease of accrual of representative series of patients for robust clinical trials that could sustain informed evidence-based therapeutic decisions to optimize the quality of patient care.

A case of mucosa-associated lymphoid tissue lymphoma of the gastrointestinal tract showing extensive plasma cell differentiation with prominent Russell bodies

A 73-year-old Japanese woman was hospitalized for detailed examination of nausea, diarrhea and loss of appetite. Atypical erosion in the ileum was found on endoscopy. Biopsy of this erosion showed proliferation of cells containing numerous Russell bodies. Differential diagnoses considered were Russell body enteritis, crystal-storing histiocytosis, Mott cell tumor, immunoproliferative small intestinal disease(IPSID) and mucosaassociated lymphoid tissue(MALT) lymphoma. The cells containing prominent Russell bodies showed diffuse positivity for CD79 a and CD138, but negative results for CD20, CD3, UCHL-1, CD38 and CD68. Russell bodies were diffusely positive for lambda light chain, but negative for kappa light chain, and immunoglobulin(Ig)G, Ig A and Ig M. Based on these findings, Russell body enteritis, crystal-storing histiocytosis and IPSID were ruled out. As the tumor formed no mass lesions and was restricted to the gastrointestinal tract, MALT lymphoma with extensive plasma cell differentiation was finally diagnosed. The patient showed an unexpectedly aggressive clinical course. The number of atypical lymphocytes in peripheral blood gradually increased and T-prolymphocytic leukemia(T-PLL) emerged. The patient died of T-PLL 7 mo after admission. Autopsy was not permitted.

Low grade gastric mucosa associated lymphoid tissue lymphoma:Treatment strategies based on 10 year follow-up

AIM:To deduce strategic guidelines of gastric mucosa associated lymphoid tissue lymphoma (MALTOMA) by evaluating the long-term outcome of patients in respect to various treatment modalities.METHODS:A total of 55 patients with MALTOMA from May 1992 to August 2002 were retrospectively reviewed.RESULTS: Complete remission was obtained in 24 (82.8%) of 29 patients treated with anti Helicobacter pylori(H pylori) regimen only. The duration to reach complete remission was 12 months (85 percentile, 2-33 months).Five patients showed complete remission with radiation therapy (26-86 months).Two of them were Hpyloritreatment failure cases.CONCLUSION: Hpylorieradication is an effective primary treatment option for low grade MALTOMA and radiation therapy could be considered in patients with no evidence of Hpyloninfection or who do not respond to Hpylorieradication therapy 12 months after successful eradication.

Mucosa-associated lymphoid tissue lymphoma of the transverse colon: A case report

We herein present a case of a 75-year-old female with mucosa-associated lymphoid tissue (MALT) lymphoma of the transverse colon with the stage IE (Ann Arbor clas- sifi cation). Colonoscopy revealed the tumor’s appearance as a IIa plus ?Research Society for Cancer of Colon, Rectum and Anus, measuring less than 2 cm in diameter. Histologically, the tumor was diagnosed as MALT lymphoma because of the presence of lymphoepithelial lesions consisting of diffuse proliferation of atypical lymphocytes and glandular de- struction. The majority of these lymphocytes immunohis- tochemically stained for the B-lymphocyte marker. The patient fi rst underwent H pylori eradication therapy withLansap?. However, the tumor size gradually increased over the next 4 mo and the patient eventually underwent surgical resection. The operative procedure included a partial colectomy with dissection of the paracolic lymph nodes. The tumor measured 45 mm x 30 mm in diam- eter and histological examination showed that the lym- phoma cells had infi ltrated the muscle layer of the colon without nodal involvement. The patient has had no re- currence postoperatively without any chemotherapy.

Clinical outcomes of radiation therapy for early-stage gastric mucosa-associated lymphoid tissue lymphoma

AIM:To evaluate the clinical outcomes of radiation therapy(RT)for early-stage gastric mucosa-associated lymphoid tissue lymphoma(MALToma).METHODS:The records of 64 patients treated between 1998 and 2011 were analyzed retrospectively.For Helicobacter pylori(H.pylori)-positive patients(n=31),chemotherapy or H.pylori eradication therapy was the initial treatment.In patients with failure after H.pylori eradication,RT was performed.For H.pylorinegative patients(n=33),chemotherapy or RT was the first-line treatment.The median RT dose was 36Gy.The target volume included the entire stomach andthe perigastric lymph node area.RESULTS:All of the patients completed RT without interruption and showed complete remission on endoscopic biopsy after treatment.Over a median follow-up period of 39 mo,the 5-year local control rate was 89%.Salvage therapy was successful in all relapsed patients.Secondary malignancies developed in three patients.The 5-year overall survival rate was 94%.No patient presented symptoms of moderate-to-severe treatmentrelated toxicities during or after RT.CONCLUSION:Radiotherapy results in favorable clinical outcomes in patients with early-stage gastric MALToma who experience failure of H.pylori eradication therapy and those who are H.pylori negative.

Remission of primary low-grade gastric lymphomas of the mucosa-associated lymphoid tissue type in immunocompromised pediatric patients

我们报导联系 mucosa 的淋巴组织(麦芽) 的主要胃的淋巴瘤的宽恕在二免疫打损害小儿科的病人。病人 1，在免疫的一个 14 岁的男孩损害了未知原因的状态，抱怨了重复腹的疼痛。考试与本地侵略和淋巴节点参与揭示了胃的麦芽。浆液 anti-Helicobacter pylori (H pylori ) 抗体是积极的。H pylori 根除被沉溺于它的不利效果。麦芽损害自发地在没有为淋巴瘤的任何治疗的下一 24 个月的 regressed。病人 2，一个 6 岁的男孩，为 adrenoleukodystrophy 的治疗经历了脐带血移植。他是为在移植以后的 graft-versus-host 疾病的管理抑制免疫力的药。恶心和便血出现了，进一步的考试与 H pylori 胃炎揭示了胃的麦芽。独自为 H pylori 感染由药组成的治疗根除了 H pylori 并且完全也解决了病人的麦芽损害。病人们 1 和 2 被跟随在上面在 10 年和 3 年的经期上，分别地没有恶化的任何症状。在结论， MALT 类型的胃的淋巴瘤能被保守疗法甚至在免疫治好损害小儿科的病人。

Management of gastric mucosa-associated lymphoid tissue lymphoma in patients with extra copies of the MALT1 gene

AIM To identify the clinical features of gastric mucosaassociated lymphoid tissue(MALT) lymphoma with extra copies of MALT1.METHODS This is a multi-centered,retrospective study. We reviewed 146 patients with MALT lymphoma in the stomach who underwent fluorescence in situ hybridization analysis for t(11;18) translocation. Patients were subdivided into patients without t(11;18) translocation or extra copies of MALT1(Group A,n = 88),patients with t(11;18) translocation(Group B,n = 27),and patients with extra copies of MALT1(Group C,n = 31). The clinical background,treatment,and outcomes of each group were investigated.RESULTS Groups A and C showed slight female predominance,whereas Group B showed slight male predominance. Mean ages and clinical stages at lymphoma diagnosis were not different between groups. Complete response was obtained in 61 patients in Group A(69.3%),22 in Group B(81.5%),and 21 in Group C(67.7%). Helicobacter pylori(H. pylori) eradication alone resulted in complete remission in 44 patients in Group A and 13 in Group C. In Group B,14 patients underwent radiotherapy alone,which resulted in lymphoma disappearance. Although the difference was not statistically significant,event-free survival in Group C tended to be inferior to that in Group A(P = 0.10).CONCLUSION Patients with t(11;18) translocation should be treated differently from others. Patients with extra copies of MALT1 could be initially treated with H. pylori eradication,similar to patients without t(11;18) translocation or extra copies of MALT1.

Colonic mucosa-associated lymphoid tissue lymphoma identified by chromoendoscopy

Colonic mucosa-associated lymphoid tissue(MALT)lymphomas are a rare occurrence and the definitive treatment has not been established.Solitary or multiple,elevated or polypoid lesions are the usual appearances of MALT lymphoma in the large intestine and sometimes the surface may reveal abnormal vascularity.Herein,we report a case of MALT lymphoma and review the relevant literature.Upon colonoscopy,a suspected pathologic lesion was observed in the proximal transverse colon.The lesion could be distinguished more prominently after using narrowband imaging mode and indigo carmine-dye spraying chromoendoscopy.Histopathologic examination of this biopsy specimen revealed lymphoepithelial lesions with diffuse proliferation of atypical lymphoid cells effacing the glandular architecture and centrocyte-like cellsinfiltrating the lamina propria.Immunohistochemical analyses showed that tumor cells were positive for CD20 and Bcl-2e,and negative for CD10,CD23,and Bcl-6.According to Ann-Arbor staging system,the patient had stage IIE.A partial colectomy with dissection of the paracolic lymph nodes was performed.Until now,there is no recurrence of lymphoma at follow-up.

Clinical features and treatment outcomes of primary ocular adnexal mucosa-associated lymphoid tissue lymphoma: a single center retrospective analysis of 64 patients in China

AIM: To investigate the clinical features, treatment and prognosis of primary ocular adnexal mucosa-associated lymphoid tissue lymphoma(POAML).METHODS: A retrospective analysis was performed on 64 patients with POAML who were admitted to the First Affiliated Hospital of Zhengzhou University from January 2006 to December 2018.RESULTS: With a median follow-up of 61 mo(range, 2-156 mo), estimated overall survival(OS) rate and progressionfree survival(PFS) rate at 10 y reached 94.5% and 61.5%, respectively. Median OS time and PFS time were not reached. During this period, only 3 patients died, but none of them died directly due to disease progression. One patient(1.6%) developed transformation to diffuse large B-cell lymphoma(DLBCL). Of the 56 patients achieved complete remission after first-line treatment, 5(8.9%) developed local and/or systemic relapse eventually. Patients ≥60 y had significantly shorter PFS than younger patients(P=0.01). For patients with early stages(Ann Arbor stage I and stage II), univariate analysis confirmed that radiotherapydose lower than 32 Gy were independently associated with shorter PFS(P=0.04). Other factors including gender, bone marrow involvement, the initial location of the disease, and the laterality were not associated with PFS.CONCLUSION: The data from our center indicate that POAML has a slow clinical progression and has an excellent clinical outcome. Patients with POAML harbor a continual risk of relaps and transformation to aggressive subtype of lymphoma.

Primary renal mucosa-associated lymphoid tissue lymphoma, the result of chronic pyelonephritis?

Objective: To report 2 cases of primary renal marginal zone B-cell lymphomas of mucosa-associated lymphoid tissue (MALT lymphoma), and observe the relations between this rare tumor of kidney and chronic pyelonephritis. Methods: 2 renal MALT lymphomas were collected from referral consultation. Detailed clinical information were reviewed, morphological analysis based on the HE section, and immunohistochemistry were performed by CD20, CD79a, CD5, CD10, CD43, CD23, BCL10 and Cyclin D1 antibodies. Results: 2 female patients with age of 48 and 55, respectively, all had a history of chronic pyelonephritis. Under the B ultrasonic and CT scanning a bump in the kidney was found. Renal carcinoma suspected and hereby the whole nephrectomy performed. In the macroscopic, tumors were laid in the renal medulla, with dark red color and ill-defined boundary. In the microscopic, there were mixed lymphoid cells infiltrate which mainly consisted of small lympho- cytes, centrocyte-like cells, lymphoplasmacytoid and plasma cells, reactive follicles and lymphoepithelial lesions also could be seen in the lesion, but follicles colonization was rare. In fact, except changes of lymphoma, basic renal disease also could be seen. Most glomeruli were atrophic, some glomeruli were hyperplastic and hypertrophic. Tubules were dilated or contacted, many dilated tubules contained pink-color glassy-appearing casts that suggest the appearance of thyroid tissue. As a result, those 2 cases showed juxtaposed changes of lymphoma and pyelonephritis. Immunohistochemistry showed that tumor cells were CD20 and CD79a positive, CD43 was weak positive, but CD5, CD10, CD23, BCL10 and Cyclin D1 were all negative. Conclusion: Primary renal MALT lymphoma was very rare disease. According to the clinical manifestation, it’s hard to differentiate from renal cell carcinoma. But the morphological features were consistent with the classic MALT lymphomas in other sites. Immunophenotypic profiles were helpful for diagnosis. Based on the truth that many MALT lymphomas in other sites were connected with chronic inflammations, we suppose that the renal MALT lymphoma may originate from chronic pyelonephritis.