MALT lymphoma

H. pylori is one of the main causes of human chronic gastritis, resulting in various diseases including peptic ulcers, gastric adenocarcinomas, and mucosa-associated lymphoid tissue (MALT) lymphomas (Williams... 

Recent studies have shown that MALT lymphomas are associated with t(l 1 18) (q21 q21) and t(l 14)(q22 q23) (D24, LI 1, L12, R9, Y9, A2, D23,L11, W13). The latter translocation is associated with overexpression of the BCL-10 gene product in the nucleus. Although BCL-10 is expressed in gastric MALT lymphomas without the t(l 14), the presence of the t( 11 18) and expression of BCL-10 is associated with higher stage disease (D23, Lll). Furthermore, MALT lymphomas confined to the stomach (stage IE) with t(ll 18) do not respond to H. pylori eradication (D24, L10, Y7). 

N. L., CD5+ extranodal marginal zone B-cell (MALT) lymphoma. A low grade neoplasm witii a propensity for bone marrow involvement and relapse. Am. J. Clin. Pathol. 105, 31—37 (1996). 

Isaacson, P. G., Muller-Hermelink, H. K., Piris, M. A., Berger, F., Nathwani, B., Swerdlow, S. H., and Harris, N. L., Extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma). In World Health Organization Classification of Tumours. Pathology and Genetics of Tumours of Haematopoietic and Lymphoid Tissues (E. S. Jaffe, N. L. Harris, H. Stein, and J. W. Vardiman, eds.), pp. 157-160. IARC Press, Lyon, 2001. 

FIGURE 33-2. The natural history of Helicobacter pylori infection in the pathogenesis of gastric ulcer and duodenal ulcer, mucosa-associated lymphoid tissue (MALT) lymphoma, and gastric cancer. 

Testing for HP is only recommended if eradication therapy is considered. If endoscopy is not planned, serologic antibody testing is a reasonable choice to determine HP status. Posttreatment evaluation to confirm eradication is unnecessary in most patients with PUD unless they have recurrent symptoms, complicated ulcer, MALT lymphoma, or gastric cancer. The UBT is the preferred nonendoscopic method to verify HP eradication after treatment. To avoid confusing bacterial suppression with eradication, the UBT must be delayed at least 4 weeks after the completion of treatment. The term eradication or cure is used when posttreatment tests conducted 4 weeks after the end of treatment do not detect the organism. Quantitative antibody tests are considered impractical for posttreatment eradication as antibody titers remain elevated for long periods of time. 

Mucosa-associated lymphoid tissue (MALT) lymphoma... 

Cavalli F, Isaacson PG, Gascoyne RD, Zucca E. MALT lymphomas. Hematology (Am Soc Hematol Educ Program) 2001 241-258. 

Immunoproliferative small intestinal disease (IPSID) is a disorder related to extranodal MALT lymphoma that is prevalent in populations living around the Mediterranean Sea. Although mucosal plasma cells expressing... 

TABLE 6.4 Recurrent Molecular and Genetic Findings in Malt Lymphoma ... 

IgA without light chains predominate, at different stages IPSID has marginal zone lymphocytes or large transformed lymphs similar to non-Mediterranean cases of MALT lymphoma. 

A detailed number of characteristic cytogenetic and molecular findings have been described in MALT lymphomas and are listed in Table 6.4. These abnormalities provide an insight into the anatomic site of involvement, clinical manifestations, and behavior of these lymphomas. 

T(3 i4)(Pi4 Q32) This chromosome abnormality is detected in approximately 10% of MALT lymphomas. The translocation results in the Forkhead box protein Pl(FOXPl) joining with the IGFI enhancer region on chromosome... 

This translocation is more commonly seen in MALT lymphomas involving ocular adnexa, skin, and thyroid. The presence of trisomy 3 has also been noted in this subset of MALT lymphomas. 

T(i i4)(P22 Q32) AND T(i i4)(P22 Q32) These translocations, though quite specific for MALT lymphomas, are only present in about 1% to 2% of cases. The translocation places the BCLIO and gene on chromosome lp22 under the control of the IGH enhancer region on chromosome 14 or under regulation by IgLx. Both translocations result in an overexpression of nuclear BCLIO and similarly resultant in activation of the NF-kB pathway, as does the t(ll 18)(q21 q21). 

Diss TC, Wothetspoon AC, Speight P, et al. B-cell monoclonal-ity, Epstein Batt virus, and t(14 18) in myoepithelial sialadenitis and low-gtade B-cell MALT lymphoma of the patotid gland. Am J Surg Pathol. 1995 19(5) 531-536. 

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