You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
isaacson and wright first used the term mucosa - associated lymphoid tissue ( malt ) lymphoma in 1983 and these malt lymphomas are of interest as they arise from sites normally devoid of lymphoid tissue .
they are frequently preceded by chronic inflammatory disorders ( usually autoimmune in character ) that result in the accumulation of lymphoid tissue ( 1 ) .
the gastrointestinal tract is the most frequently involved extranodal location for malt lymphomas and the stomach is the most common site for malt lymphomas of the gastrointestinal tract .
colonic malt ( mucosa - associated lymphoid tissue ) lymphomas have not been well investigated when compared to stomach malt lymphomas .
most of the colonic malt lymphomas present as a protruding mass and/or an ulceration . here
we report the first case of a mucosa - associated lymphoid tissue lymphoma manifesting itself colonoscopy as multiple mucosal discolorations alone and some localized granularity of the colonic mucosa in a 47-yr - old patient .
complete remission was achieved with anti - cancer polychemotherapy and radiation therapy and he has been free of disease for 14 months .
a 47-yr - old man suffering from tenesmus and mucoid stool was admitted to our hospital via a local clinic .
he had smoked one pack of cigarettes daily for 20 yr and he did not drink alcohol .
he had a history of pulmonary tuberculosis 20 yr ago that was treated with anti - tuberculosis medication for 9 months . on admission
, he appeared in good health without any complaints of weight loss , fever and night sweats .
his blood pressure was 110/90 mmhg , his pulse rate was 78/min , body temperature was 36.2 and respirations were 18/min .
on physical examination , the patient appeared normal and showed no remarkable findings except a depressed anterior chest wall .
the laboratory findings included hemoglobin 13.4 g / dl , white blood cells 4,600/l , platelets 305,000/l , ast 22 iu / l , alt 35 iu / l , alp 47 iu / l , ggt 42 iu / l , ldh 393 u / l , bun 14.8 mg / dl , creatinine 1.0 mg / dl , uric acid 6.2 mg / dl and calcium 3.6 mg / dl .
a radiograph of the chest showed a white lesion in the right upper lung field ; this was thought to be a healed scar from pulmonary tuberculosis .
colonoscopic examination revealed two lesions 1 ) a granular & reddish mucosal thickening at the just above rectum ( fig .
1a ) , and 2 ) a reddish inflammatory mucosa without elevation or depression at the appendiceal orifice ( fig .
1b ) . microscopic examination of the mucosal lesions of the colon and rectum showed lymphoepithelial lesions consisting of diffuse proliferation of small lymphocytes and some glandular destruction by lymphocytes ( fig .
we then started to perform the staging evaluation of non - hodgkin 's lymphoma ( nhl ) .
the proteins showed a pattern of polyclonal gammopathy upon serum protein electrophoresis . computed tomography of abdomen revealed no lymphadenopathy .
he was diagnosed with a low grade malt lymphoma of stage ie ( using ann - arbor staging ) and stage ii ( using st .
he had received anticancer chemotherapy ( cyclophosphamide 1,200 mg , adriamycin 80 mg , vincristine i.v . and
prednisolone 100 mg p.o . for 5 days every month for 4 months ) with involved field radiation therapy ( 3,000 cgy at the colon and 150 cgy at the rectum with 10 mv radiography 2 ports for 20 times during 29 days ) . his presenting symptoms , including the tenesmus and mucoid stools subsided after treatment .
three months after treatment , a follow - up colonoscopy revealed no abnormal mucosa ( fig .
marginal zone b - cell lymphomas account for approximately 8% of all nhl , among which , they are the third most frequent histologic subtype ( after the diffuse large b - cell lymphoma and the follicular lymphoma ) ( 2 ) . the group of lymphomas classified as marginal zone b - cell lymphomas include a number of extranodal b - cell lymphomas defined as extranodal marginal zone b - cell lymphomas of malt type in the revised european - american classification of lymphoid neoplasms ( real classification ) ( 3 ) and in the new who classification of neoplastic diseases of the hematopoietic and lymphoid tissue ( 4 ) .
the stomach is the most common site of extranodal marginal zone b - cell lymphomas of malt type , however , malt lymphomas have also been described in intestitinal tract ( 5 , 6 ) .
the small intestine , especially ileum is the most common site of intestinal malt lymphoma .
malt lymphomas are also found in the colon in the following order of frequency ; rectum , ascending colon , transverse colon , sigmoid colon and descending colon ( 7 ) . according to a recent report from korea ( 8) ,
endoscopically , there are various morphologic features in gastric malt lymphoma , revealed as irregular geographic superficial ulcer ( 43.7% ) , diffuse mucosal nodularity ( 25% ) , erosion ( 18.7% ) , atrophy ( 6.3% ) and mucosal elevation ( 6.3% ) ( 16 ) .
most of the colonic lymphomas except lymphomatous polyposis present as sessile protuberant or ulcerative lesions ( 6 , 9 , 10 ) .
colonic malt lymphoma often appears as a single mass , the most commonly in the ileocecal valve area ( 10 ) . in the previous reports of colonic malt lymphoma in korea
, malt lymphomas of the colon appeared endoscopically as polyps ( 8 , 11 ) .
we report a case of colonic malt lymphoma not identified as a protruding mass or polyp , but as a mucosal change that was found endoscopically .
it is thought that the erythematous discoloration of the appendiceal orifice and the granularity in the rectum may be the early mucosal discolorization and minimal granularity in malt lymphoma .
we think that extra caution is needed when observing for not only the mucosal morphology , but also for discolorations .
we have not seen a report of colonic malt lymphoma identified ( as happened in our case ) by simple mucosal discolorations .
the onset of malt lymphoma in the stomach is preceded by the acquisition of a mucosa - associated lymphoid tissue ( malt ) ; this is generally the result of an infection by h. pylori ( 12 , 13 ) .
the eradication of h. pylori with antibiotics can be effectively used as the sole initial treatment of localized ( i.e. , confined to the gastric wall ) gastric malt lymphoma .
however , antibiotic treatments seem to suppress but not eradicate the neoplastic clone , and malt lymphoma relapses have been seen years after treatment .
molecular follow - up studies revealed the persistence of the malignant clone in more than 50% of the cases in histologic remission after the antibiotic therapy .
therefore , a careful long - term follow - up is mandatory for all of the patients who have received antibiotic treatment for h. pylori ( 14 ) .
the metastatic ability and sensitivity against chemotherapy of the colonic malt lymphoma is not known . in colonic malt lymphomas
, the literature suggests that surgical resection of localized lesion may be the best choice ( 15 ) . in the present case ,
combination of multi - agent chemotherapy and radiotherapy was effective , though a long - term follow - up is definitively needed .
because colonic malt lymphoma presents with various features , meticulous observation is mandatory in colonoscopic evaluations .
as mentioned above , we think that mucosal biopsy of the discolored but not protruding and/or ulcerative mucosa is also needed for ruling out lymphoma .
most colonic multiple mucosa - associated lymphoid tissue ( malt ) lymphomas are confirmed with a histologic and immunohistochemical staining of the mucosal biopsy specimen obtained during colonoscopic examinations . 
 endoscopically , colonic malt lymphomas frequently appear as protruding and/or ulcerative lesions , and there are not so many reports of colonic malt lymphoma as compared to the frequent reports of malt lymphoma of stomach . 
 we report a unique case of colonic malt lymphoma presenting as a simple reddish discoloration of mucosa ; this presentation has never been describe before . 
 our patient was a 47-yr - old male who suffered from tenesmus and mucoid stool . 
 a colonoscopy was accomplished , followed by a histologic examination and we diagnosed a colonic malt lymphoma . 
 staging of the disease was done because this was necessary for choosing the modality of treatments . 
 the patient was then treated with polychemotherapy in conjunction with radiation therapy .