Letteratura scientifica selezionata sul tema "Intraepithelial lymphoma"

Lymphoma is the most common malignant hematopoietic neoplasm in domestic felines. Twenty-two cases of feline epitheliotropic duodenal T-cell lymphoma were characterized morphologically and immunohistochemically (CD3, Pax5, Ki-67), and Bcl-2 immunoexpression was established. Most cases were in domestic shorthair cats (88.2%), with a mean age of 11.2 years. All lymphomas were CD3+, with a low-to-moderate expression of Ki-67 (<30%). A correlation between the tumoral pattern of infiltration in the lamina propria and the intraepithelial distribution of the neoplastic lymphocytes was established (p = 0.0155). Intraepithelial nests of neoplastic lymphocytes were predominantly observed in lymphomas with a patchy distribution in the lamina propria, whereas intraepithelial plaques were seen in lymphomas with an obliteration pattern. Bcl-2 was expressed in neoplastic cells in all cases, and a higher expression was associated with increased villous stunting (p = 0.0221), and tended to be present in those cases with increased epithelial damage. The expression of Bcl-2 and the degree of epitheliotropism were correlated with neoplastic progression in epitheliotropic intestinal T-cell lymphomas; those displaying high Bcl-2 immunoexpression showed increased villous stunting and epithelial damage, suggesting that Bcl-2 is overexpressed in advanced tumor stages, and may be used as a predictor of tumoral behavior in feline epitheliotropic intestinal T-cell lymphomas. This entity showed many similarities with human MEITL, so the latter entity should be considered in further lymphoma classifications of domestic animals.

Abstract Mucosa-associated lymphoid tissue (MALT) lymphomas usually arise at sites of acquired MALT and are uncommon in native MALT (eg, Peyer patches and tonsil). Malignancy in these low-grade lymphomas is often inferred by immunoglobulin light-chain restriction and expression of CD43; molecular genetic evidence is sought only if these are in doubt. We report 6 cases (4 tonsils, 2 appendixes) of marginal zone (MZ) hyperplasia in children aged 3 to 11 years that, despite histologic and immunophenotypic features indicative of lymphoma, were polyclonal by molecular analysis. No lymphoma-directed therapy was given and patients remain alive and well (5 cases, median follow-up 35.3 months). The involved tonsil and appendix showed florid MZ hyperplasia with prominent intraepithelial B cells (IEBCs). The MZ B cells and IEBCs showed a high-proliferation fraction and a CD20+, CD21+, CD27-, immunoglobulin (Ig) superfamily receptor translocation-associated 1-positive (IRTA-1+), CD43+, multiple myeloma oncogene 1 (MUM-1), IgM+D+ phenotype. Polymerase chain reaction (PCR), cloning, and sequencing of rearranged IgH and Igλ genes (whole tissue sections [6 cases]; microdissected cells [2 cases]) showed that the MZ B cells and IEBCs were polyclonal and the IgH genes nonmutated. In contrast, MZ (intraepithelial) B cells of 6 control tonsils had a similar immunophenotype, except for expression of CD27 and polytypic light chains, whereas molecular studies showed that they were polyclonal with mutated Ig genes. (Blood. 2004;104:3343-3348)

Abstract Intestinal T-cell lymphoma is a heterogenous group. These tumors differ in their association with enteropathy, intraepithelial or nonintraepithelial origin, primary or secondary involvement, and T-cell or natural killer–like T-cell immunophenotype. There are also nonneoplastic conditions, such as celiac disease, refractory sprue, and reactive T-cell infiltration that mimic intestinal T-cell lymphoma. Therefore, the differential diagnosis requires extensive morphologic, immunophenotypic, and molecular genetic studies. A subset of primary intestinal intraepithelial T-cell lymphoma has emerged in recent years that is distinguished from enteropathy-type T-cell lymphoma in terms of clinical presentation (nonenteropathic), morphology (monomorphic small to medium-sized cells), immunophenotype (CD3−CD8+CD56+), and cytogenetics. We report such a case with a unique immunophenotype (CD3−, cytoplasmic CD3+, CD4−, CD8+, CD5−, CD7+, CD16−, CD56+, CD57−, CD103+, T-cell intracellular antigen 1+, and βF1+) that is comparable to that of a newly identified subset of intraepithelial T cells. The tumor progressed rapidly and the patient died within 6 months after the onset of the disease. We recommend a large monoclonal antibody panel for the differential diagnosis of this heterogeneous group of T-cell lymphoma.

Abstract Background: Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a disease involving the intestine and is often diagnosed in surgically resected specimens. The disease prognosis of MEITL is fatal because of rapid recurrence and leakage after excision. Recently, in microscopic finding of MEITL, intraepithelial lymphocytosis in mucosa that were grossly intact has been reported. In this study, we evaluated the intraepithelial lymphocytosis of the resection margin to determine the reason for the early recurrence or leakage in MEITL. Materials and Methods: We reviewed the medical records of all patients who were diagnosed with small intestine lymphoma from January 1995 to June 2018 at our medical center. We analyzed a tissue array from 8 patients diagnosed with MEITL. The expression of CD3, CD5, and CD8 were analyzed by immunohistochemistry. Results: A total of 8 cases of small intestine lymphoma were collected in this period. There were three men (37.5%) and five women (mean age 55 years). Two patients died without initiation of chemotherapy. Six patients received chemotherapy after resection of MEITL (4 patients received CHOP regimens, 2 patients received ProMACE-CyBOM regimens), but five patients died within 6 months (mean survival time 4.1 months, range 0.3-12.1 months). Only one patient survived for 5 years. On gross examination, the distance to the resection margin was 7.58 cm (3.8-14.0 cm) on average. Microscopic examination revealed intraepithelial lymphocytosis at least of one of the resected margins in all case. Immunohistochemical staining for CD3, CD5, and CD8 was performed on the resection margins. As a result, severe intraepithelial lymphocytosis accompanied by aberrant loss of CD5 was observed in 6 cases (75%). Conclusion: In the MEITL, an intraepithelial lymphocytosis accompanied by aberrant CD5 loss is frequently observed in the resection margin, even if the resection margin is grossly intact, and there is no clear microscopic involvement of the lymphoma especially on low power. This fact is thought to be related to the early recurrence or leakage of MEITL at the surgical site. Disclosures No relevant conflicts of interest to declare.

Abstract We report the case of a large natural killer (NK)–like T-cell lymphoma that involved the ileum and displayed a distinct immunophenotype and complex karyotype. The patient exhibited no evidence of gluten-sensitive enteropathy (celiac disease) or any other type of enteropathy as determined by clinical history, endoscopy, and serology for immunoglobulin A (IgA) antiendomysial and IgG antigliadin antibodies. Molecular studies demonstrated a clonal T-cell receptor γ chain gene rearrangement. Immunophenotype analysis showed expression of intestinal epithelium-homing receptor CD103, CD7, cytoplasmic CD3ɛ, CD56, and CD16 but no other T- or NK-cell markers. Cytogenetic analysis of the malignant cells revealed multiple chromosomal abnormalities indicative of a biologically advanced, high-grade lymphoma. A novel subset of normal intestinal intraepithelial lymphocytes, bearing a similar phenotype, has been described; moreover, this subset diminishes, rather than expands, in gluten-sensitive enteropathy. This case supports the notion that lymphomas involving the small intestine represent a heterogeneous group of lymphomas with diverse pathogenetic mechanisms.

Human enteropathy-associated T-cell lymphoma (EATL) is considered to be derived from intraepithelial lymphocytes (IELs); however, the origin of canine intestinal T-cell lymphoma (ITCL) remains unclear. Histological, immunohistochemical, and clonality examinations were performed using endoscopically collected canine duodenum samples of mucosal lesions of chronic enteropathy (CE; 73 cases) and ITCL without transmural neoplastic mass lesions (64 cases). Histopathological examinations revealed the intraepithelial accumulation of lymphocytes (called “intraepithelial lymphocytosis”) in 54/73 CE cases (74%) and the epitheliotropism of neoplastic lymphocytes in 63/64 ITCL cases (98%). Immunohistochemically, IELs in CE with intraepithelial lymphocytosis (IEL+CE) were diffusely immunopositive for CD3, with scattered immunopositivity for CD5, CD8, CD20, and granzyme B (GRB). The percentage of CD8+ in CD3+ IELs was significantly lower in IEL+CE than in CE without intraepithelial lymphocytosis (IEL−CE). Double-labeling immunohistochemistry revealed a high percentage of GRB expression in CD8− IEL among IEL+CE. Among 64 ITCL cases, CD3 was immunopositive in 64 (100%), CD5 in 22 (34%), CD8 in 8 (13%), CD20 in 12 (19%), CD30 in 13 (20%), and GRB in 49 (77%). In CD3+ cells, Ki67 immunopositivity was highest in ITCL, intermediate in IEL+CE, and lower in IEL−CE. A clonal TCR gene rearrangement was detected in 1/19 IEL−CE cases (5%), 15/54 IEL+CE (28%), and 38/58 ITCL (66%). These results indicate that the immunophenotype of canine ITCL (CD8−GRB+) is similar to that of the increased IELs in CE. The high proliferative activity and clonality of T cells in IEL+CE suggest that canine ITCL originates from these IELs, similar to human EATL.

A small subset of coeliac disease (CD) patients experiences persisting or recurring symptoms despite strict adherence to a gluten-free diet (GFD). When other causes of villous atrophy have been excluded, these patients are referred to as refractory celiac disease (RCD) patients. RCD can be divided in two types based on the absence (type I) or presence (type II) of an, usually clonal, intraepithelial lymphocyte population with aberrant phenotype. RCDI usually runs a benign course and may be difficult to be differentiated from uncomplicated, slow responding CD. In contrast, RCDII can be defined as low-grade intraepithelial lymphoma and frequently transforms into an aggressive enteropathy associated T-cell lymphoma with dismal prognosis. This paper describes the clinical characteristics of RCDI and RCDII, diagnostic approach, and the latest insights in treatment options.

The intestinal immune system, which must ensure appropriate immune responses to both pathogens and commensal microflora, comprises innate lymphoid cells and various T-cell subsets, including intra-epithelial lymphocytes (IELs). An example of innate lymphoid cells is natural killer cells, which may be classified into tissue-resident, CD56bright NK-cells that serve a regulatory function and more mature, circulating CD56dim NK-cells with effector cytolytic properties. CD56bright NK-cells in the gastrointestinal tract give rise to indolent NK-cell enteropathy and lymphomatoid gastropathy, as well as the aggressive extranodal NK/T cell lymphoma, the latter following activation by EBV infection and neoplastic transformation. Conventional CD4+ TCRαβ+ and CD8αβ+ TCRαβ+ T-cells are located in the lamina propria and the intraepithelial compartment of intestinal mucosa as type ‘a’ IELs. They are the putative cells of origin for CD4+ and CD8+ indolent T-cell lymphoproliferative disorders of the gastrointestinal tract and intestinal T-cell lymphoma, NOS. In addition to such conventional T-cells, there are non-conventional T-cells in the intra-epithelial compartment that express CD8αα and innate lymphoid cells that lack TCRs. The central feature of type ‘b’ IELs is the expression of CD8αα homodimers, seen in monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), which primarily arises from both CD8αα+ TCRαβ+ and CD8αα+ TCRγδ+ IELs. EATL is the other epitheliotropic T-cell lymphoma in the GI tract, a subset of which arises from the expansion and reprograming of intracytoplasmic CD3+ innate lymphoid cells, driven by IL15 and mutations of the JAK-STAT pathway.

Abstract Abstract 2722 Enteropathy-associated T-cell lymphoma (EATL) is a rare intestinal lymphoma that arises from intraepithelial lymphocytes. Clinical outcome of patients with EATL is very poor, due to chemotherapy-resistance and high relapse rates. Therefore, new therapeutic options for EATL are urgently needed. Studies in other types of lymphoma have shown that inhibition of apoptosis may cause chemotherapy-resistance and that restoration of defective apoptosis can induce cell death in these lymphomas. Preliminary data in EATL samples have demonstrated an increased expression of a fraction of NF-κB target genes, suggesting upregulation of NF-κB activity in EATL tumor cells. NF-κB activity can be inhibited by the proteasome inhibitor bortezomib resulting in induction of apoptosis. In the present study, we evaluated if apoptosis is inhibited in EATL cells and if Bortezomib can restore apoptosis in EATL cells. Laser-capture microdissection was applied to 16 fresh frozen EATL samples to obtain purified tumor cells for RNA isolation. Intraepithelial lymphocytes (IEL) of healthy controls were obtained from fresh duodenal biopsies and isolated by cell sorting. RT-MLPA analysis revealed that the pro-apoptotic BH3-only gene Noxa was significantly downregulated in most EATL samples compared to healthy donor IEL. Induction with etoposide resulted in caspase-9 mediated apoptosis in EATL cells with relatively high Noxa expression, whereas in EATL cells with low Noxa expression no apoptosis was induced, suggesting an inhibition in the intrinsic apoptosis pathway. Treatment with Bortezomib resulted in induction of apoptosis in EATL cells. The lethal dose (LD50) varied between 7.5 nM and 15 nM. Bortezomib induced cell death in EATL cells was caspase-9 mediated. mRNA and protein expression analysis showed upregulation of Noxa after incubation with bortezomib. In conclusion, our study showed that bortezomib induces apoptosis by upregulation of Noxa in EATL cells. Bortezomib therefore may be a potential drug in the treatment of patients with EATL. Disclosures: No relevant conflicts of interest to declare.

Abstract Enteropathy-associated T-cell lymphoma, an often fatal complication of celiac disease, can result from expansion of aberrant intraepithelial lymphocytes in refractory celiac disease type II (RCD II). Aberrant intraepithelial lymphocytes and lymphoma cells are intracellularly CD3ϵ+ but lack expression of the T-cell receptor (TCR)–CD3 complex on the cell surface. It is unknown what causes the loss of TCR-CD3 expression. We report the isolation of a cell line from an RCD II patient with the characteristic phenotype of enteropathy-associated T-cell lymphoma. We demonstrate that in this cell line the TCR-α and -β chains as well as the CD3γ, CD3δ, CD3ϵ, and ζ-chains are present intracellularly and that assembly of the CD3γϵ, CD3δϵ, and ζζ-dimers is normal. However, dimerization of the TCR chains and proper assembly of the TCR-CD3 complex are defective. On introduction of exogenous TCR-β chains, but not of TCR-α chains, assembly and functional cell surface expression of the TCR-CD3 complex were restored. Defective synthesis of both TCR chains was found to underlie loss of TCR expression in similar cell lines isolated from 2 additional patients. (Pre)malignant transformation in RCD II thus correlates with defective synthesis or defective association of the TCR chains, resulting in loss of surface TCR-CD3 expression.

La maladie cœliaque réfractaire de type II (MCRII), autrement appelé lymphome intraépithélial, est une complication rare mais sévère de la maladie cœliaque caractérisée par une expansion clonale d'une population particulière de lymphocytes intraépithéliaux (LIE) innés, présents dans l'intestin normal chez l'Homme comme chez la souris. Notre laboratoire a montré que cette population particulière de LIE innés partage des caractéristiques communes à celles des lymphocytes T et des cellules NK. Ces « LIE iCD3+ innés » sont caractérisées par une expression de CD3 au niveau intracellulaire mais pas à la surface, de récepteurs NK et présentent des réarrangements des gènes codant le récepteur T. En outre, le laboratoire a montré que ces cellules se développent dans l'épithélium intestinal à partir de précurseurs de la moëlle osseuse en réponse à une combinaison de signaux induits à travers la voie NOTCH et l'interleukine 15. Durant la lymphomagénèse, les LIE iCD3+ innés acquièrent des mutations somatiques gain-de-fonction dans JAK1et/ou STAT3. Ces mutations pourraient favoriser l'expansion clonale des LIE iCD3+ mutés aux dépens des lymphocytes T normaux résidents en leur conférant une sensibilité accrue à l'interleukine 15 (IL-15), une cytokine surexprimée dans l'intestin des patients. Ainsi, notre hypothèse est que ces mutations ont un rôle central dans l'initiation de la lymphomagénèse dans un contexte de production chronique d'IL-15 et, de ce fait, représentent une cible thérapeutique. Le premier objectif de ma thèse a été d'étudier l'intérêt des inhibiteurs de la voie JAK/STAT dans le traitement de la MCRII. Dans un premier temps, nous avons testé in vitro différents inhibiteurs de JAK/STAT sur des lignées cellulaires IL-15-dépendantes issues soit de LIE de MCRII soit de LIE T normaux. Nous avons démontré que ces drogues inhibent la prolifération et la phosphorylation de STAT3 et augmentent l'apoptose cellulaire aussi bien dans les LIE MCRII que dans les LIE T normaux. Dans un second temps, nous avons généré un modèle de xénogreffe en injectant des cellules issues de biopsies intestinales ou du sang d'un patient MCRII dans des souris immunodéficientes surexprimant l'IL-15 humaine dans l'épithélium intestinal (Rag-/-Gc-/-IL-15TgE ou IRGC) afin de tester l'efficacité des inhibiteurs de JAK/STAT in vivo. Le traitement des souris xénogreffées par le ruxolitinib, inhibiteur de JAK1/JAK2, a permis une diminution de la fréquence et du nombre ainsi que de l'activité cytotoxique des cellules tumorales humaines et une amélioration de l'état général des souris. Ces résultats encourageants restent à confirmer. Le second objectif de ma thèse a été de vérifier si la mutation pD661V de STAT3 était suffisante pour induire le développement de la MCRII dans un contexte de surproduction d'IL-15 dans des souris IRGC. Nous avons généré avec succès les LIE iCD3+ innés murins semblables aux LIE iCD3+ innés humaines à partir de précurseurs communs aux cellules lymphoïdes (CLP) en combinant un signal NOTCH et IL-15. Nous avons ensuite transduit les CLP avec un vecteur rétroviral contenant Stat3 sauvage ou muté (D661V). Les cellules transduites ont alors été injectées chez des souris IRGC suivies pendant 8 semaines. Les résultats préliminaires ont montré que les LIE iCD3+ innés se logent préférentiellement dans l'intestin mais aucun développement d'un lymphome intraépithélial n'a été observé au bout de 8 semaines suggérant que la mutation pD661V de STAT3 seule ne suffit pas en présence d'IL-15 à induire in vivo un lymphome intraépithélial. Ces résultats préliminaires sont toutefois à reproduire et à confirmer. Le modèle mise en place pour l'étude de STAT3 va désormais être utilisé afin d'évaluer la contribution respective de mutations canoniques de JAK1 et STAT3 et des autres mutations récurrentes retrouvées dans le lymphome intraépithélial
Refractory coeliac disease type II (RCDII), also called intraepithelial lymphoma, is a rare but severe complication of coeliac disease characterized by the clonal expansion of a small subset of innate intraepithelial lymphocytes (IEL), present in the normal human and murine intestine. Our lab has shown that this population displays shared features between T and natural killer (NK) cells. These so-called iCD3+ innate IEL are mainly characterized by intracellular expression of CD3, which is not detected at the cell surface, expression of NK receptors as well as DNA rearrangement of T cell receptor genes. Our lab has also shown that iCD3+ innate IEL originate from bone marrow precursors through coordinated NOTCH1 and interleukin (IL)-15 signals. During lymphomagenesis, iCD3+ innate IEL of most RCDII patients were shown to have acquired somatic gain-of-function mutations in JAK1 and/or STAT3 that confer increased sensitivity to interleukin-15, a cytokine overexpressed in the intestine of coeliac patients, thereby promoting their clonal expansion. Thus, our hypothesis is that JAK1/STAT3 mutations play a key role in initiating lymphomagenesis associated to coeliac disease in an IL-15-rich environment and that they could represent an attractive therapeutic target.The first objective of my thesis was to study the interest of JAK/STAT inhibitors for RCDII treatment. First, we have tested in vitro different JAK/STAT inhibitors on IL-15-dependent RCDII or normal IEL-T cell lines. We have shown that these inhibitors decrease the proliferation and phosphorylation of STAT3 and increase cellular apoptosis in both RCDII and normal T cell lines. Secondly, we have established a xenograft model based on the injection of cells derived from biopsy or blood from one RCDII patient into immunodeficient mice overexpressing the human IL-15 transgene in their gut epithelium (Rag-/-Gc-/- IL-15TgE; IRGC) to test the efficacy of JAK/STAT inhibitors in vivo. Treatment of xenografted mice with ruxolitinib, a potent inhibitor of JAK1/JAK2 decreased the frequency, number and cytotoxic potential of human tumoral cells and allowed clinical restoration. These preliminary results are encouraging but need to be confirmed. The second objective of my thesis was to test whether the Stat3 pD661V mutation is sufficient to induce the intraepithelial lymphoma in an IL-15-rich context in IRGC mice. We have successfully generated murine iCD3+ innate IEL in vitro, resembling their human counterparts from common lymphoid precursors by combining NOTCH and IL-15 signals. We then transduced CLP with a retroviral vector containing wild-type or mutated Stat3 pD661V. The transduced cells were injected into IRGC mice that subsequently were followed-up during a period of 8 weeks. In vitro generated iCD3+ innate IEL preferentially homed to the intestine. However, no development of intraepithelial lymphoma was observed suggesting that the Stat3 pD661V variant alone is not sufficient to induce the intraepithelial lymphoma. These preliminary results need to be reproduced and confirmed. The murine model used to test the role of STAT3 will now be used to evaluate the respective contribution of canonical mutations in JAK1 and STAT3 and of other recurrent mutations identified in RCDII

O linfoma granular de células grandes felino (LGL do inglês large granular lymphocytes) é classificado pela Organização Mundial de Saúde (OMS) como um subtipo de linfoma de células T associado a enteropatia tipo I, em que as células apresentam grânulos citoplasmáticos azurófilos, visíveis no exame citológico. Na maioria dos casos, o linfoma LGL desenvolve-se na mucosa do intestino delgado, principalmente no jejuno, com envolvimento posterior de outros órgãos e possível leucemia LGL secundária. Estes gatos apresentam um quadro clínico gastrointestinal (GI), com aumento segmentar do intestino, que com o tempo evolui para uma massa tumoral facilmente detetável durante o exame clínico. No entanto, existem casos reportados sem envolvimento GI. É um subtipo de linfoma raro, que apresenta um comportamento biológico muito agressivo na maioria dos casos, e não é comumente descrito na literatura. Todos os estudos publicados mostram tempos de sobrevida mais baixos em comparação com outros subtipos de linfoma, com fraca resposta à quimioterapia. No entanto, alguns casos esporádicos, apresentam um melhor prognóstico. Fenotipicamente, tanto os LGL neoplásicos como os linfócitos intra-epiteliais (IEL do inglês Intra-epithelial lympchocytes) expressam CD103 (αEβ7) e CD8αα, o que sugere que estes linfomas possam ter origem nestas células. Para além disso, o linfoma LGL felino pode ter um processo inflamatório na sua génese, evoluindo para um processo crónico, ocorrendo uma estimulação antigénica prolongada que leva a uma transformação clonal das células T intraepiteliais intestinais. Contudo, a origem numa inflamação crónica do intestino, permanece por ser confirmada. Assim, foi objetivo desta revisão descrever este linfoma de forma aprofundada, discutindo a sua possível origem e fatores de prognóstico. Esta revisão visa também contribuir para impulsionar estudos futuros que permitam incrementar o conhecimento sobre esta doença.
Large granular lymphoma (LGL large granular lymphocytes) is classified by the World Health Organization (WHO) as a subtype of T-cell lymphoma associated with enteropathy type I, in which cells have azurophilic cytoplasmic granules visible on cytological examination. In most cases, LGL lymphoma develops in the mucosa of the small intestine, mainly in the jejunum, with posterior involvement of other organs and possible secondary LGL leukemia. These cats present a clinical signs of gastrointestinal (GI) disease, with segmental increase of the intestine, which over time evolves to an tumor mass easily detectable during clinical examination. However, there are cases reported without GI involvement. Feline LGL lymphoma is a rare lymphoma that exhibits a very aggressive biological behavior in mos cases, and is not commonly described in the literature. All published studies show lower survival rates compared to other lymphoma subtypes, having a very poor response to chemotherapy. However, sporadic cases present a better prognosis. Phenotypically both neoplasic LGL and intraepithelial lymphocytes (IEL Intra-epithelial lymphocytes) express CD103 (αEβ7) and CD8αα, suggesting that these lymphomas may arise from these cells. In addition, this subtype of lymphoma can develop from an inflammatory process that evolves into a chronic stage, in which the prolonged antigenic stimulation stimulates the intraepithelial T cells to go trought a clonal transformation. However, the origin of the chronic inflammation of the intestine remains unknown. Thus, the objective of this review was to describe this lymphoma in depth, discussing its possible origin and prognostic factors. This review also aims to contribute to future research to increase knowledge about this disease.

Primary gastrointestinal lymphoma is the most common extranodal lymphoma and is almost exclusively of non-Hodgkin type. It is defined as lymphoma that has presented with the main bulk of disease in the gastrointestinal tract, with or without involvement of contiguous lymph nodes. MALT lymphoma is an indolent B-cell lymphoma whose histology recapitulates the features of mucosa-associated lymphoid tissue (MALT). It most commonly affects the stomach, presenting with nonspecific dyspepsia. Most cases appear to be driven by Helicobacter pylori, with 75% regressing following eradication of the organism with appropriate antibiotics. Deeply invasive lymphomas and those with adverse histological or cytogenetic features are unlikely to respond. Mantle cell lymphoma and follicular lymphoma are adult B-cell lymphomas that can present as gastrointestinal lymphomas. Diffuse large B-cell lymphoma is an aggressive lymphoma that is relatively frequently encountered in gastrointestinal locations. Burkitt’s lymphoma is also an aggressive B-cell lymphoma, and is the most frequent childhood gastrointestinal lymphoma. Enteropathy-associated T-cell lymphoma is an intestinal lymphoma of intraepithelial T lymphocytes that occurs most commonly in the jejunum or ileum and is associated with coeliac disease. It presents with abdominal pain, often due to intestinal perforation. The prognosis is usually poor, with death frequently resulting from abdominal complications in patients already weakened by uncontrolled malabsorption.

Coeliac disease (CD) is an immune-mediated disorder affecting the small intestine. The condition represents an intolerance to gluten. Removal of dietary gluten permits recovery, with a full recovery for the majority of affected subjects. A percentage of affected subjects who do not improve with a gluten-free diet are considered to have refractory coeliac disease (RCD). Refractory coeliac disease is subdivided into type 1, characterised by a polyclonal expansion of intraepithelial lymphocytes (IELs) that have a normal phenotype, and type 2 (RCD2) which exhibits IELs with a monoclonal phenotype. Subjects with RCD carry a high risk of complications, including ulcerative jejunitis and lymphoma affecting the small intestine, the latter termed enteropathy-associated T-cell lymphoma (EATL).

Non-inflammatory pathologies of conjunctiva refer to conjunctival diseases or conditions that do not have infectious or immune inflammatory origin. This chapter includes disorders such as conjunctivochalasis, conjunctival cysts, conjunctival lymphangiectasias, conjunctival lymphoma, dermoids, papilloma, intraepithelial neoplasia, nevi and other rarely seen tumors, conjunctival degenerations and changes related to aging, xerosis, as well as interesting cases of fastidious conjunctivitis. Some cases of neoplasia have before and after treatment illustration to highlight the possibility of medical treatment against surgical interventions. At the end of this chapter, some observations are added to show the anatomical changes of conjunctiva without any underlying disease or inflammation.