Abstract
Ocular adnexa MALT-lymphomas represent approximatively 5-15% of all extranodal lymphomas. Almost 75% of OAMLs are localized in orbital fat, while 25% of cases involves conjunctive. MALT-lymphomas often recognize specific environmental factors responsible of lymphoma development and progression. In particular as Helicobacter pylori in gastric MALT lymphomas, other bacterial infections have been recognized related to MALT lymphomas in specific site. Recently Chlamydia psittaci has been identified in Ocular Adnexa MALT lymphomas, with variable frequence dependently from geographic areas. Thus bacterial infection is responsible of clonal selection on induced MALT with subsequent lymphoma development. Moreover Chlamydia psittaci could promote chromosomal aberration either through genetic instability as a consequence of induced proliferation and probably through DNA oxidative damage. The most common translocation described in MALT lymphomas affects NF-kB pathway with a substantial antiapoptotic effect. Several therapeutic approaches are now available, but the use of antibiotic-therapy in specific cases, although with conflicting results, could improve the treatment of ocular adnexa MALT lymphomas. In this review we analyse the most relevant features of Ocular adnexa MALT lymphomas, underlining specific biological characteristics mainly related to the potential role of Chlamydia psittaci in lymphomagenesis.
Highlights
Non-Hodgkin’s lymphomas represent the most common ocular adnexa neoplasm [1]
It has been recorded that Ocular Adnexal mucosa-associated lymphoid tissue (MALT) Lymphoma (OAML) increases by more than 6% for year
Chromosomal aberrations involving mainly MALT1 and bcl10 genes with consequent deregulation of their gene expression are commonly observed in MALT lymphomas, but with different distribution dependently from specific anatomic regions, being t(11;18) more frequent in gastric MALT lymphomas and t (14;18) in extragastric MALT
Summary
Non-Hodgkin’s lymphomas represent the most common ocular adnexa neoplasm [1]. Approximately accounting 515% of all extranodal lymphomas localize at ocular adnexa, including the conjunctiva, the lachrymal gland, the orbital fat, the eyelid and the lachrymal sac [2]. A recent study on ocular adnexal MALT lymphoma cases from six geographic areas showed marked variation of the association between infection and OAML among the regions examined, being most frequent in Germany (47%), followed by the USA (35%), and the Netherlands (29%), but relatively low in central Italy (13%), the UK (12%) and southern China (11%) [15]. In a case of conjunctival MALT lymphoma has been reported yet another new translocation, the t(5;11) (q33;p11.2), not previously described [103] Another possible mechanism for uncontrolled NF-kB activation in MALT lymphoma, in the ocular adnexa, salivary gland and thyroid MALT lymphoma, is generated by homozygous deletion of the chromosomal band 6q23 with subsequent loss of the tumor necrosis factor alpha-induced protein 3 (TNFAIP3, A20) [104], an essential global NF-kB inhibitor. Cp DNA was not detectable in peripheral blood mononuclear cells of the six patients, and after a median follow-up of 31 months, three patients achieved an objective response [126]
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