Colonic Mucosa-associated Lymphoid Tissue Lymphoma Research Articles

Primary MALT lymphoma of the colon - Pathohistological and immunohistochemical analysis, prognosis and complex treatment

Colonic MALT lymphoma is a rare disease. Due to rare diagnosis, randomized studies are missing to determine the optimal therapeutic approach. We present a 77-year-old patient with Mucosa-Associated Lymphoid Tissue (MALT) lymphoma of the colon, which is diagnosed after colonoscopy with biopsy and precise pathohistological and immunohistochemical analysis. Treatment includes surgery /hemicolonectomy, followed by 6 cycles of chemotherapy- R-COPP regimen. Two years after diagnosis, the patient is in good condition with normal quality of life without recurrence and distant spread of the disease. Through this article, our goal is to support medical literature with another clinical case that demonstrate the need for thorough and precise diagnosis by immunohistichemic analysis and an assessment of optimal complex treatment. Keywords: MALT lymphoma; non-Hodgkin's lymphoma; pathohistological analysis; immunohistochemical analysis; chemotherapy; Complex treatment.

Clinicopathologic Findings in Patients With Initial Diagnosis of Extranodal Marginal Zone B-Cell Lymphoma of Mucosa-Associated Lymphoid Tissue (MALT) in Colorectal Mucosa.

To evaluate clinicopathologic features, management, and behavior of colorectal extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT). Clinical data, laboratory studies, and radiographic records were reviewed (2005-2018), and fluorescence in situ hybridization studies were performed. Eleven patients were identified, six of whom were discovered as an incidental finding on endoscopy. Morphologic and immunophenotypic features were similar to MALT lymphomas at other sites except that lymphoepithelial lesions were uncommon. Three of nine patients were positive for BIRC3/MALT1 fusions, two of whom had identical B-cell clones identified in subsequent gastric biopsy specimens. Eight of 10 patients had no clinically evaluable disease after observation (±antibiotics; n = 4) or radiation/chemotherapy (n = 4). Patients with incidental and localized colonic MALT lymphoma demonstrated an excellent prognosis with conservative management, although longer follow-up and data based on consistent staging and surveillance methods (including gastric evaluation) are necessary for informed management.

S1614 Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma Isolated to the Colon

INTRODUCTION: Mucosa-associated lymphoid tissue (MALT) lymphoma is a rare non-Hodgkin B-cell lymphoma commonly seen in the stomach but can be found anywhere in the gastrointestinal tract. We present a patient found to have MALT lymphoma of the colon during a screening colonoscopy, which was initially thought to be a laterally spreading sessile serrated lesion. CASE DESCRIPTION/METHODS: A 56-year-old female presented for colorectal cancer screening. She reported having chronic abdominal pain and new increase in stool frequency in the setting of a rise in life stressors. The colonoscopy revealed a 4 cm Paris 0-IIa-IIc polyp of the transverse colon and the patient was referred for repeat exam with endoscopic mucosal resection of the lesion. During the colonoscopy, the polyp was lifted without issue but proved difficult to entrap in various polypectomy snares. A few small pieces of the polyp were eventually removed and collected while the rest of the lesion was left in situ and tattoos applied proximally and distally. Histology revealed marginal zone lymphoma. Computed tomography of the chest, abdomen, and pelvis was negative for metastatic disease and confirmed Stage 1 MALT lymphoma. H. pylori stool antigen test was positive and Strongyloides stercoralis IgG antibody was negative. A multi-disciplinary team decided that a transverse colectomy would be the best treatment strategy based on the patient’s wishes. The patient tolerated the transverse colectomy well. Her medical oncologist advised clinical follow up and imaging (as the lesion was visible on CT preoperatively) every six months for five years as well as repeat colonoscopy at 1 year from surgery. Finally, she was treated for H. pylori infection with quadruple therapy. DISCUSSION: MALT lymphoma of the colon is exceedingly rare. While treatment for gastric MALT lymphomas is well established, management of colonic MALT lymphoma is not. Treatment options can consist of surgical resection, chemotherapy, or radiation therapy based on staging. Although guidelines for Stage 1 colonic MALT lymphoma recommend surgical resection, a multi-disciplinary approach is essential. H. pylori infection is rarely associated with MALT lymphoma in the colon. Results are mixed regarding H. pylori treatment in these individuals, although there have been reports of lymphoma resolution following eradication therapy. Overall this case demonstrated the importance of a multidisciplinary approach in a rare case that was initially thought to be a lateral spreading lesion.Figure 1.: Paris 0-IIa-IIc polyp measuring 4.0 cm in the transverse colon.Figure 2.: Endoscopic mucosal resection (EMR) of the identified polyp.Figure 3.: H&E, ×400: High-power image of lymphoepithelial lesion, where neoplastic cells are invading the colonic epithelium.

S1795 Incidental Finding of a MALT Lymphoma of the Rectum

INTRODUCTION: Extranodal marginal zone lymphomas of the mucosa-associated lymphoid tissue (MALT) are a subtype of Non-Hodgkin lymphoma (NHL), accounting for only 5% of all NHL. MALT lymphomas can be found in different tissues of the body, the stomach being the most commonly affected gastrointestinal site. Primary colorectal MALT lymphoma is a rare entity and few cases have been reported in the literature; its presentation is often indistinguishable from that of other colonic malignancies, or it can be found incidentally during screening colonoscopies. CASE DESCRIPTION/METHODS: We report the case of an asymptomatic 51-year-old female with a family history of colorectal cancer who underwent routine screening colonoscopy. Prior colonoscopies performed since age 40 were unremarkable. Colonoscopy revealed a subepithelial nodule in the recto-sigmoid colon (Figure 1). Subsequently, a lower endoscopic ultrasound (EUS) was performed and revealed a 15 mm polypoid multi-lobulated lesion with central umbilication in the recto-sigmoid colon. Endosonographically, the lesion was hypoechoic, and it appeared to be confined to both the luminal interface/superficial mucosa and deep mucosa without evidence of extension into the submucosa or muscularis propria. The lesion was successfully removed in its entirety by endoscopic mucosal resection (EMR). The procedure was uneventful, and the patient was discharged home the same day. Pathology revealed large intestinal mucosa of the rectum with extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (Figure 2). Immunohistochemistry demonstrated lymphoid cells that were positive for CD20 (Figure 3), CD23, and BCL2 but negative for CD3, CD5, CD43, CD10, and BCL6; confirming the above diagnosis. Whole-body positron emission tomography did not reveal systemic extension. Repeat colonoscopy 3 months later revealed visually prominent infiltration at post-mucosectomy scar negative for residual lymphoma on biopsy. However, due to a strong concern for submucosal spread on site, a decision was made to start radiation therapy. DISCUSSION: The treatment for patients with MALT lymphoma includes surgical resection, chemotherapy, and radiation among others. However, due to the rarity of colonic MALT lymphomas, the optimal treatment modality for them is not well defined and though its prognosis tends to be excellent, periodic surveillance colonoscopies are needed due to increased risk for other primaries and localized recurrence or transformation into higher-grade disease in some instances.Figure 1.: A subepithelial nodule is seen in recto-sigmoid colon during endoscopy.Figure 2.: Rectal mucosa with dense infiltration of lymphoid cells (H&E, 50x).Figure 3.: Diffuse expression of CD20 on immunohistochemical staining suggests lymphoid infiltrate to be composed mostly of B-cells (50x).

Mucosa-Associated Lymphoid-Tissue Lymphoma of the Descending Colon in a Patient with Blastocystis hominis Infection: A Case Report and Review of Literature

Mucosa-associated lymphoid tissue (MALT) lymphoma is an extra nodal marginal zone B-cell lymphoma that has been associated with chronic infections. It affects especially stomach, but other organs of gastrointestinal tract can be also involved. Colon MALT lymphoma is a very rare disease. We report a case of large bowel MALT lymphoma diagnosed as a result of weight loss and positive occult fecal blood test. Blastocystis hominis infection was detected in fecal analysis. We hypothesize chronic parasitic infection could be related with the development of the lymphoma.

Colonic mucosa-associated lymphoid tissue in a renal transplant recipient: a case report

BackgroundExtra-gastric (particularly colonic) lymphoma of mucosa-associated lymphoid tissue in the immunosuppressed solid organ transplant recipient is rare. We report a case of low-volume mucosa-associated lymphoid tissue lymphoma with colonic and bone marrow involvement in a renal transplant recipient that has been managed conservatively.Case presentationA 62-year-old Caucasian man, 14 years after kidney transplantation, was diagnosed as having extra-nodal marginal zone lymphoma of mucosa-associated lymphoid tissue with bone marrow and colonic involvement, after a colonoscopy identified mucosa-associated lymphoid tissue lymphoma in a sessile sigmoid polyp following surveillance fecal occult blood testing that returned a positive result. A gastric biopsy showed no evidence of Helicobacter pylori, but Helicobacter pylori immunoglobulin G was positive. He received Helicobacter pylori eradication treatment and is being managed expectantly. Immunosuppression was unchanged with prednisolone, mycophenolate mofetil, and cyclosporine A. Renal allograft function has remained stable.ConclusionsThis case highlights the unexpected occurrence of colonic mucosa-associated lymphoid tissue lymphoma in a kidney transplant recipient. The case emphasizes the importance of histopathological diagnosis of colonic lesions in this patient cohort because the unusual diagnosis of low-volume mucosa-associated lymphoid tissue lymphoma can be managed expectantly as it does not appear to be clinically aggressive in the immunosuppressed solid organ transplant.

Colonic mucosa-associated lymphoid tissue lymphoma: a case series

Primary colonic mucosa-associated lymphoid tissue (MALT) lymphoma accounts for less than 0.5% of all colon cancers. We report 9 cases of colonic MALT lymphomas (median follow up: 9 [IQR 1–26] years). The disease was multi-focal in 4 patients: the most frequent sites were the cecum in 4 and the rectum in 3 patients. The main endoscopic finding was a polypoid lesion. The treatment modalities were rituximab +/− an alkylating agent (n = 5), an alkylating agent alone (n = 2), surgical resection (n = 1), and endoscopic resection (n = 1). Remission was achieved in 8 cases. Three patients relapsed, and 2 were re-treated. At the end of the study period, 67% of the patients were in remission. All patients were symptom-free. This current series of colonic MALT lymphomas shows the indolent nature of the disease, which may be treated with various modalities.

Mass-forming mucosa-associated lymphoid tissue lymphoma of the cecum treated by laparoscopy-assisted bowel resection

Colonic mucosa-associated lymphoid tissue (MALT) lymphoma is very rare, especially those which form a mass. Although the characteristics and treatment methods of gastric MALT lymphomas are well established, those of colonic MALT lymphomas have been insufficiently described. Here, we report a case of mass-forming cecal MALT lymphoma that was successfully treated by laparoscopy-assisted bowel resection. A 60-year-old woman with right lower abdominal pain and a palpable tumor was referred to our hospital. Colonoscopy showed a smooth elevated submucosal tumor-like lesion in the cecum. Histological and immunochemical findings were consistent with MALT lymphoma. Serum tumor marker levels were within normal range. Enhanced abdominal computed tomography showed a large tumor 55mm in diameter in the cecum and edema of a few paracolic lymph nodes. The tumor was diagnosed as cecal MALT lymphoma classified as stage II1 by Lugano classification, and laparoscopy-assisted ileocecal resection was performed. The postoperative course was uneventful and the patient underwent eradication therapy for Helicobacter pylori. A year after the operation she has had no recurrence. In patients with mass-forming colonic MALT lymphoma without dissemination, surgical resection may be a feasible treatment.

Beyond the Borders of the Gastric Lumen: A Rare Case of Colonic MALT Lymphoma

Colonic mucosa-associated lymphoid tissue (MALT) lymphoma is a rare subtype of marginal zone B-cell non-Hodgkin's Lymphoma (NHL) owing to 2.5% of cases. It also requires more aggressive measures than that of its gastric variant, as seen in the case below. A 56 year old asymptomatic male with a medical history of diabetes, hypertension, hyperlipidemia, and family history positive for colorectal cancer presented to his outpatient gastroenterologist for a surveillance colonoscopy. His last was 5 years prior and notable for two benign tubular adenomas. Repeat colonoscopy revealed two 5 and 10 mm sessile polyps in the transverse and sigmoid colon respectively, which were resected and sent for analysis. Pathology demonstrated atypical lymphoid proliferation, with extranodal marginal zone lymphoma of mucosa associated lymphoid tissue (MALT lymphoma) localized to the sigmoid colon. FISH testing was negative for rearrangement involving MALT1. He was subsequently referred to oncology for further workup to assess the extent of his disease. MALT lymphoma, an uncommon variant of marginal zone B-cell NHL, arise from multiple extra-nodal locations, with the gastrointestinal tract serving as the most common site. Gastric MALT lymphomas have been well documented in the literature, consisting of approximately 60-75% of cases with colonic MALT lymphoma representing a mere 2.5%. Unlike our patient who was asymptomatic on presentation, the majority have abdominal pain as their leading complaint. While management of gastric MALToma has been well-established with treatment consisting of antibiotic therapy targeting H. pylori, there is currently no standard of care for its colonic counterpart. Debates on treatment modalities for both localized versus disseminated disease demonstrate a need for standardization of therapy. In addition, an overall poor prognosis of non-gastric MALToma with five and ten year survival rates of approximately 50 and 20%, respectively, also calls for a more aggressive approach-- such as prompt workup to assess the extent of disease and ensuring regular surveillance as seen in our patient. We present this case to raise physician awareness of this disease to aid in prompt diagnosis and management of this rare entity with the hopes of improving survival.1473_A Figure 1. Sessile polyp, Sigmoid Colon1473_B Figure 2. Sessile polyp, Sigmoid Colon

Mucosa-Associated Lymphoid-Tissue Lymphoma of the Cecum and Rectum: A Case Report.

A colonic mucosa-associated lymphoid-tissue (MALT) lymphoma is relatively rare compared to lymphomas of the stomach or small intestine. We present a case of a MALT lymphoma in the cecum and rectum found during screening colonoscopy. A 54-year-old female, who had undergone right-breast-conserving surgery with axillary dissection due to an invasive ductal carcinoma and a left-breast excisional biopsy due to microcalcification following adjuvant chemoradiation therapy 3 years earlier, was found to have 3-mm-sized smooth elevated lesions in both the cecum and rectum. No pathologic lesion or lymphadenopathy was found at any other site, but chronic gastritis negative for Helicobacter pylori infection was found. The polyps were removed by using an endoscopic biopsy and revealed an extra nodal marginal zone B-cell MALT lymphoma, showing positive for CD3 and CD20 by immunohistochemical staining. The patient underwent close observation without any additional treatment and has shown no evidence of recurrence as of her last visit.

Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma of the Colon: A Case Report and a Literature Review

Patient: Female, 56Final Diagnosis: Colonic MALT lymphomaSymptoms: Epigastric painMedication: —Clinical Procedure: Colonoscopy and biopsySpecialty: Gastroenterology and HepatologyObjective:Rare diseaseBackground:Non-Hodgkin lymphoma (NHL) is a well-known hematologic malignancy. The gastrointestinal (GI) tract is the most commonly involved extra nodal site. MALT lymphomas are uncommon, accounting for 5% of all NHL. Gastric mucosa-associated lymphoid tissue (MALT) lymphoma is the prototype seen in association with Helicobacter pylori. Colonic MALT lymphoma is rare and comprises only 2.5% of the MALT lymphomas. Its etiology and treatment is not well established.Case Report:A 56-year-old Hispanic woman presented to the clinic with symptoms of chronic epigastric pain for the past three years and a 13-pound weight loss over the past two months. The patient did not have any prior medical conditions. Her systemic examination was unremarkable, while her routine labs revealed mild anemia. An upper endoscopy and colonoscopy for colorectal cancer screening were performed revealing erosive gastropathy with duodenal ulcers and a 5 cm broad based polypoid mass in the hepatic flexure respectively. Computed tomography (CT) of the abdomen revealed a round, well demarcated mass at the hepatic flexure of the colon. The histopathology and immunophenotyping were consistent with extra nodal marginal zone of MALT lymphoma. Stool testing for H. pylori was positive. The patient received two weeks of H. pylori eradication therapy and four cycles of rituximab. Repeat colonoscopy after completion of chemotherapy showed complete resolution of the MALT lymphoma.Conclusions:Unlike gastric MALT lymphoma, treatment of colonic MALT lymphoma is not standardized. Chemotherapy and surgical resection have been utilized to successfully treat it. Only a handful of cases have reported successful treatment of colonic MALT lymphoma with rituximab monotherapy.

Colonic Mucosa-Associated Lymphoid Tissue Lymphoma Presented as Multiple Polyposis at Colonoscopy in a Nigerian Man: Case Report of a Rare Occurrence and Brief Review of Literature.

Colonic Mucosa-Associated Lymphoid Tissue Lymphoma Presented as Multiple Polyposis at Colonoscopy in a Nigerian Man: Case Report of a Rare Occurrence and Brief Review of Literature.

Su1622 Asymptomatic Colonic Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma Found Incidentally on Colonoscopy: A Case Series and Review of Treatment Guidelines

Su1622 Asymptomatic Colonic Mucosa-Associated Lymphoid Tissue (MALT) Lymphoma Found Incidentally on Colonoscopy: A Case Series and Review of Treatment Guidelines

Endoscopic features of lymphoproliferative diseases

Lymphoproliferative diseases of the digestive tube are rare diseases with a large spectrum of clinical manifestations and endoscopic features. This video production (Video 1, available online at www.giejournal.org) presents in detail the endoscopic, histologic, and radiologic findings along with the clinical background and management of several distinct endoscopic presentations of gastric mucosa-associated lymphoid tissue (MALT) lymphoma (Fig. 1A), duodenal follicular lymphoma, posttransplantation lymphoproliferative disorder of the duodenum (Fig. 1B), colonic MALT lymphoma, solitary rectal plasmacytoma, and high-grade diffuse large B cell colorectal lymphoma. The purpose of this video is to familiarize gastroenterologists with the endoscopic manifestations of lymphoproliferative diseases and their management.

Colonic MALT Lymphoma

Introduction: An asymptomatic 54-year-old male referred for surveillance colonoscopy had biopsies from a thickened sigmoid fold, suggesting a mucosa-associated lymphoid tissue (MALT) lymphoma. Pathology showed atypical lymphocytic infiltrate involving mucosa and submucosa with intense CD20+ infiltrate. Colonoscopy 5 years earlier showed hyperplastic and adenomatous polyps. He denied constitutional symptoms, exposure to radiation, history of malignancy, and previous H. pylori infection. The physical exam did not show lymphadenopathy. CBC, lactate dehydrogenase, serum, or urine protein electrophoresis, and a CT of the chest, abdominal, and pelvis were normal. Endoscopic ultrasound showed a minimally thickened colonic mucosa, normal submucosa, muscularis mucosa, and no regional lymphoadenopathy. H. pylori stool antigen test was negative, but empiric antibiotic treatment was given. A colonoscopy was repeated in 1 year and showed a flat granular 2-cm lesion at 30 cm. Endomucosal resection and cautery of the resection edges were performed with tattooing of the site. Pathology from the polypectomy showed atypical lymphoid proliferation with CD20+ B cells arranged in a nodular and merging pattern, expanding beyond the lamina prioria. These findings were consistent with a MALT lymphoma. CD3 and CD5 showed a few clusters of T cells within the B cells. CD21 highlighted interconnected clusters of follicular dendritic cells. CD10 was negative. CD138 showed rare isolated plasma cells. The patient was referred to surgery for a successful laparoscopic sigmoid resection with negative margins. Colonic MALT lymphoma is a rare clinical entity, has an unknown etiopathogenesis, and may present asymptomatically. A reported association with H. pylori infection exists but is not present in the majority of cases. Antibiotic treatment, even without documentation of H. pylori infection, has been reported to resolve colonic MALT lymphomas. Our case demonstrated failure to eradicate colonic MALT lymphoma with empiric H. pylori antibiotic treatment. Review of the literature shows most cases are treated with complete endoscopic resection or surgical resection, although chemotherapy, radiation, and strict observation have also been used for treatment.

A Rare Case of Mucosa-Associated Lymphoma of the Colon

Case Report: A 73-year-old man presented to the emergency room with complains of bright red per rectum associated with lower abdominal pain. He had generalized weakness with decreased oral intake for 1 month prior to admission. Physical exam was significant for mild tenderness to palpation in the right upper abdomen with no guarding and rebound tenderness. On colonoscopy, there was a 2-cm polypoid fold at the hepatic flexure. Biopsy of the lesion showed mixed lymphoid infiltrate consisting of atypical lymphoid cells with pale cytoplasm and irregular nuclei. Immunohistochemistry was positive for CD 20 and negative for CD 5 and cyclin D1, confirming the diagnosis of marginal zone B-cell lymphoma. The tumor was resected on subsequent colonoscopy. Discussion: Mucosa-associated lymphoid tissue (MALT) is present in the bowel as Payer’s patches. Interestingly, the most common site of presentation of gastrointestinal MALT lymphomas is the stomach, which is devoid of Payer’s patches. Chronic infection with H. pylori causes development of MALT lymphomas in the stomach. Colonic MALT lymphomas are very rare, accounting for 2.5% of the total gastrointestinal MALT lymphomas; their association with H. pylori infection is not clear. The diagnosis of MALT lymphoma is made by histopathology. An estimated 65% of the cases have reported cure of gastric MALT lymphomas after eradication of H. pylori bacteria in the stomach. Because of low incidence, the treatment of MALT lymphomas of the colon is still not well defined. Surgery has been shown to be the treatment of choice for localized lesions. However, MALT lymphomas have shown a propensity to remain localized and be confined to the regional lymph nodes for a long time, which raises the question whether surgery with its associated risks is appropriate. Another alternative is radiotherapy, which has shown to provide 99% response rate in both gastric and thyroid MALT lymphomas. Close follow-up is required for colonic MALT lymphoma because of limited knowledge on recurrence and prognosis. The gross appearance of lymphoma on colonoscopy also varies considerably and we would recommend biopsies of any abnormal mucosal lesion noted on surveillance colonoscopy.Figure 1

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 narrow-band 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 cells infiltrating 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.

A case of mucosa-associated lymphoid tissue lymphoma of the sigmoid colon presenting as a semipedunculated polyp.

Mucosa-associated lymphoid tissue (MALT) lymphomas are characterized by lymphoepithelial lesions pathologically. Colonic MALT lymphomas are relatively rarer than lymphomas of the stomach or small intestine. Endoscopically, colonic MALT lymphoma frequently appears as a nonpedunculated protruding polypoid mass and/or an ulceration in the cecum and/or rectum. We report a unique case of a colonic MALT lymphoma presenting as a semipedunculated polyp. A 54-year-old man was found to have a 2-cm semipedunculated polyp in the sigmoid colon during screening colonoscopy. The polyp was removed by endoscopic mucosal resection. Histologic examination of the resected polyp revealed diffuse epithelial infiltration by discrete aggregates of lymphoma cells. We diagnosed the tumor as low-grade B-cell MALT lymphoma by immunohistochemical staining.

Malt Lymphoma of the Colon: a Rare Occurrence

Non-Hodgkin's lymphoma (NHL) is one of the leading causes of cancer in the US. NHL can be seen in the gastrointestinal tract in extralymphatic presentation. Primary GI lymphomas are rare. When present, they are more common in the stomach and small bowel. The most common histologic subtype affecting the gastrointestinal tract and colon is diffuse large B cell lymphoma. These are generally aggressive and are composed of rapidly proliferating cells of B cell origin. The second most common colorectal lymphoma is mucosa-associated lymphoid tissue (MALT)-associated low-grade B cell lymphoma. MALT-associated lymphomas are low-grade tumors arising from B cells associated with mucosal immunity. MALT is predominantly found in the gastrointestinal tract and plays a vital role in immune surveillance, mucosal regeneration, and in carcinogenesis. In the colon, lymphoid tissue consists of isolated lymphoid follicles which are composed mainly of B lymphocytes. These cells occasionally undergo abnormal proliferation and give rise to lymphoma of the MALT type. Colonic MALT lymphoma is a rare entity of increasing recognition, for which no definitive treatment has been established. There are very few case reports of colonic MALT type lymphoma given its uncommon occurrence, thereby lacking sufficient data required in evaluation, management, and treatment of these patients. We describe a rare case of colon marginal-zone B cell lymphoma of MALT (MALT lymphoma) found on routine colonoscopy. Case Presentation

A case of colonic mucosa-associated lymphoid tissue lymphoma observed under endoscopy with narrow-band imaging

A case of colonic mucosa-associated lymphoid tissue lymphoma observed under endoscopy with narrow-band imaging