The pathogenesis of EMZL is largely unknown. However, it is generally believed that both chronic antigen stimulation and acquired genetic alterations are involved.
7 8 For instance, in gastric EMZL
Helicobacter pylori has been shown to be present in most cases.
9 More recently, a possible connection between ocular region EMZL and
Chlamydia psittaci has been suggested.
10 However, these results have not been substantiated in subsequent studies, suggesting geographical variation.
3 11 12 13 Similarly, different chromosomal abnormalities have been demonstrated in EMZL with various frequencies, depending on the initial anatomic site of involvement.
14 15 These include three different translocations that seem to target the same signaling pathway,
16 resulting in increased NFκB activation and decreased apoptosis (i.e., t(11;18) (q21;q21) involving API2 and MALT1, t(14;18) (q32;q21) involving IGH and MALT1, and t(1;14) (p22;q32) involving Bcl-10 and IGH).
7 The t(11;18) is prevalent in pulmonary and gastrointestinal EMZL, whereas t(14;18) is more frequent in EMZLs involving other extranodal sites, including the ocular region.
15 Of interest, in gastric EMZL aberrant nuclear Bcl-10 occurs predominantly in cases carrying t(11;18),
17 and these cases have a more aggressive course and generally do not respond to
H. pylori eradication.
18 19 More recently, a similar association between nuclear Bcl-10 and an aggressive course has been suggested for ocular region EMZL.
20