it is well established , that more than 90% of low - grade malt lymphomas are associated with h. pylori infection1 ) . indeed , the eradication of h. pylori infection has been associated with the regression of gastric malt lymphoma in 70% to 80% of patients2 , 3 ) . additional factors contribute to the development of malt lymphoma such as : environmental , microbial , immune and genetic factors . transformation of malt lymphoma has been described ; there is genetic evidence for a clonal link between low- and high - grade components4 ) . here , we report a case of high - grade hepatic malt lymphoma that occurred six years after achieving complete remission of a low - grade gastric malt lymphoma with h. pylori eradication therapy . although we were unable to obtain cytogenetic evidence , the radiological and pathologic findings suggested that the low - grade malt was transformed to a high - grade hepatic malt lymphoma . a 67-year - old woman visited our hospital with complaints of abdominal discomfort , indigestion and constipation for five days . physical examination and laboratory findings were not specific , and her performance was excellent . gastroscopic examination showed an ulcero - infiltrative lesion at the greater curvature side of the antrum ( figure 1 ) . diffuse and nodular aggregates of lymphoid cells were composed of monotonous small to medium - sized lymphocytes with round to cleaved nuclei and clear cytoplasm . in some areas , relatively large atypical lymphoid cells were also present in less than 10% of tumor cells . immunohistochemical stains were positive for cd20 and cd79a , but negative for cd45ro , cd3 , cd5 , cd23 , bcl-2 and cyclin d1 an abdominal ct scan revealed focal wall thickening on the greater curvature side of antrum without any lymph node enlargement . unfortunately , a bone marrow biopsy was not performed , thus staging work - up of the lymphoma was not fully performed . the patient was diagnosed with a low - grade gastric malt lymphoma and treated for h. pylori infection for 14 days with omeprazole 20 mg bid , clarithromycin 500 mg bid and amoxicillin 1,000 mg bid . follow - up gastroscopic examinations , one and three months after h. pylori eradication , showed marked improvement of gastric lesions . h. pylori infection was absent by rapid urease testing and histology , but malt lymphoma was still present on histology evaluation . thereafter the patient was lost to follow - up . four years later , the patient visited our hospital again with complaints of indigestion and constipation . gastroscopy showed diffuse erythematous changes of the antral mucosa with an irregular surface at the site of the previous malt lymphoma that appeared to be a scar . gastric mucosal biopsy showed well preserved foveolar epithelium , and sparsely scattered inflammatory cells in the lamina propria devoid of residual lymphoma . abdominal ct scan showed neither gastric wall thickening nor lymph node enlargement ( figure 3 ) . about two years later , the patient returned to our hospital with complaints of general weakness and epigastric discomfort . blood tests on admission showed a hematocrit of 36.1% , a white blood cell count of 4,200/mm , a platelet count of 77,000/mm , a protein of 4.6 g / dl , an albumin of 2.4 g / dl , a total bilirubin of 3.0 mg / dl ( 0.2 - 1.0 mg / dl ) , a direct bilirubin of 2.5 mg / dl ( 0.0 - 0.2 mg / dl ) , an alkaline phosphatase of 588 u / l ( 32 - 104 u / l ) , an alanine aminotransferase of 196 u / l ( 10 - 36 u / l ) , an aspartate aminotransferase of 357 u / l ( 10 - 30 u / l ) , a lactate dehydrogenase of 1,871 u / l ( 211 - 423 u / l ) , and a prothrombin time of 11.8 sec ( 10 - 14 sec ) . histological examination revealed only chronic inflammation and intestinal metaplasia with the absence of h. pylori infection and malt lymphoma ( figure 4 ) . abdominal sonography and liver mri showed multiple hepatic nodules with multiple celiac and para - aortic lymphadenopathy ( figure 5 ) . ultrasonography - guided percutaneous core needle biopsy was performed on the hepatic nodules ; histological examination revealed a patchy infiltration , of atypical lymphoid cells , replacing the liver parenchyma . the composition of the large lymphoid cells , found in the liver biopsy , was significantly increased when compared to the previous gastric malt lymphoma . immunohistochemical stains were positive for cd20 , but negative for : cd45ro , cd3 , cd5 , cd23 , bcl-2 and cyclin d1 ( figure 6 ) . immunohistochemical stains for ki-67 were performed both on the biopsy from the previous low - grade gastric malt lymphoma and the liver core biopsy . the ki-67 labeling index , from the liver biopsy sample , was much higher ( 70% ) than in the previous gastric biopsy ( 20% ) ( figure 7 ) . these pathological findings suggested a hepatic malt lymphoma that represented a transformation from the previously treated low - grade gastric malt lymphoma to a high - grade malt lymphoma . the patient , and her family , refused further treatment and her clinical status deteriorated rapidly ; she died from sepsis one month later . the malt lymphoma was first described as a distinct pathologic entity in 1983.5 ) in 1988 , it became apparent that the gastric malt lymphoma is caused by chronic h. pylori infection ; this triggers lymphoid infiltration and formation of organized lymphoid tissue6 , 7 ) . perhaps the strongest evidence is that in approximately two thirds of cases , the lymphoma regresses after treatment of the h. pylori infection2 , 3 ) . it is assumed that the initial proliferation of lymphoma cells occurs in an antigen - dependent fashion ; this explains the tendency for these lymphomas to remain anatomically localized and to respond to antibacterial therapy . given that most patients with h. pylori gastritis do not develop malt lymphoma , additional events such as environmental , microbial , immune and genetic factors must play an important role8 ) . our patient was positive for h. pylori infection ; the initial original gastric malt lymphoma completely disappeared after eradication of h. pylori infection . however , the occurrence of transformation to a high - grade lymphoma without evidence of h. pylori re - infection strongly suggests that some other pathological mechanisms , besides h. pylori infection , played a role in disease progression . the understanding of the biology of the gastric malt lymphoma has improved over the past few years . there is a common structural cytogenetic abnormality associated with this disorder , t(11;18)(q21;q21 ) , detected in 21% to 60% of cases8 - 11 ) . this translocation acts to fuse the inhibitors of apoptosis ( iap ) family api2 with the novel gene malt1 . the characterization of another , albeit less frequent recurrent translocation , t(1;14)(p22;q23 ) has led to the identification of bcl1012 , 13 ) . both translocations are known to result in activation of the central transcription factor nf-b14 ) . nf-b induction appears to drive antigen independent growth of the lymphoma cells , promoting disease dissemination and unresponsiveness to h. pylori eradication therapy8 ) . transformation of malt lymphoma has been described , and there is a genetic evidence for a clonal link between low- and high - grade components4 ) . deletion of the p16 , mutations of the p53 gene , translocation breakpoint involved in t(6;14)(p21;q32 ) , and bcl-6 have been described to be associated with transformation of the malt lymphoma15 - 17 ) . moreover , numerous investigators have sequenced immunoglobulin heavy chain ( igh ) genes , and have found frequent somatic mutations that can be ongoing18 ) . somatic hypermutations , together with isotype switch recombination , contributes to b - cell maturation . unfortunately , we could not perform cytogenetic evaluations or igh gene rearrangement analysis in our patient . however , in the pathological findings , the composition of the large lymphoid cells and the expression of the proliferation marker ki-67 were significantly increased in the hepatic nodules compared to the previous gastric malt lymphoma ; these results suggested that the hepatic nodules represented a transformation to a higher grade malignant lymphoma from the prior low - grade gastric malt lymphoma . in addition , the occurrence of high - grade transformation , even after complete remission of the original gastric lesion , its aggressive nature may suggest that our patient had one or more underlying cytogenetic abnormalities . however , the possibility that the hepatic malt lymphoma might be a newly developed and separate lesion , with no relationship to the initial low - grade gastric malt lymphoma , can not be completely excluded . in summary , we report a case of high - grade hepatic malt lymphoma that occurred six years after achieving complete remission of a low - grade gastric malt lymphoma . although we did not perform cytogenetic evaluation , the hepatic malt lymphoma was considered to represent a transformation from the gastric malt lymphoma on the basis of radiological and pathological findings . in addition , these findings suggest that the determination of a complete cure for malt lymphoma based on gastroscopic and histological findings might not be adequate . regular follow - up , even after complete remission of the original lesion , is mandatory , and cytogenetic studies should be considered in certain cases if available .