miR-146a in Myasthenia Gravis Thymus Bridges Innate Immunity With Autoimmunity and Is Linked to Therapeutic Effects of Corticosteroids.

Toll-like receptor (TLR)-mediated innate immune responses are critically involved in the pathogenesis of myasthenia gravis (MG), an autoimmune disorder affecting neuromuscular junction mainly mediated by antiacetylcholine receptor antibodies. Considerable evidence indicate that uncontrolled TLR activation and chronic inflammation significantly contribute to hyperplastic changes and germinal center (GC) formation in the MG thymus, ultimately leading to autoantibody production and autoimmunity. miR-146a is a key modulator of innate immunity, whose dysregulation has been associated with autoimmune diseases. It acts as inhibitor of TLR pathways, mainly by targeting the nuclear factor kappa B (NF-κB) signaling transducers, interleukin 1 receptor associated kinase 1 (IRAK1) and tumor necrosis factor (TNF) receptor associated factor 6 (TRAF6); miR-146a is also able to target c-REL, inducible T-cell costimulator (ICOS), and Fas cell surface death receptor (FAS), known to regulate B-cell function and GC response. Herein, we investigated the miR-146a contribution to the intrathymic MG pathogenesis. By real-time PCR, we found that miR-146a expression was significantly downregulated in hyperplastic MG compared to control thymuses; contrariwise, IRAK1, TRAF6, c-REL, and ICOS messenger RNA (mRNA) levels were upregulated and negatively correlated with miR-146a levels. Microdissection experiments revealed that miR-146a deficiency in hyperplastic MG thymuses was not due to GCs, but restricted to the GC-surrounding medulla, characterized by IRAK1 overexpression. We also showed higher c-REL and ICOS mRNA levels, and lower FAS mRNA levels, in GCs than in the remaining medulla, according to the contribution of these molecules in GC formation. By double immunofluorescence, an increased proportion of IRAK1-expressing dendritic cells and macrophages was found in hyperplastic MG compared to control thymuses, along with GC immunoreactivity for c-REL. Interestingly, in corticosteroid-treated MG patients intrathymic miR-146a and mRNA target levels were comparable to those of controls, suggesting that immunosuppressive therapy may restore the microRNA (miRNA) levels. Indeed, an effect of prednisone on miR-146a expression was demonstrated in vitro on peripheral blood cells. Serum miR-146a levels were lower in MG patients compared to controls, indicating dysregulation of the circulating miRNA. Our overall findings strongly suggest that defective miR-146a expression could contribute to persistent TLR activation, lack of inflammation resolution, and hyperplastic changes in MG thymuses, thus linking TLR-mediated innate immunity to B-cell-mediated autoimmunity. Furthermore, they unraveled a new mechanism of action of corticosteroids in inducing control of autoimmunity in MG via miR-146a.

A case of endometrial glassy cell carcinoma: a rare entity which necessitates of better understanding.

Endometrial glassy cell carcinoma (EGCC) is a rare neoplasm, accounting for 0.5% of the carcinomas in the endometrium, composed of cells with granular eosinophilic or amphophilic cytoplasm, giving it a ground glass appearance. Till date, only 14 cases of this carcinoma have been reported. In this report, we have described a case of EGCC to help define standard diagnostic criteria and better understand the course, ideal treatment, and accurate prognosis of this disease. We report a case of a 64-year-old woman diagnosed with EGCC after an abnormal pap smear. She underwent a hysteroscopy, which led to the histological diagnosis. Laparotomic total hysterectomy and bilateral salpingo-oophorectomy were performed with pelvic lymphadenectomy and peritoneal and omental biopsies. Final pathological examination confirmed the initial diagnosis. Pelvic nodes removed during surgery and peritoneal and omental biopsies were negative for tumor cells. Treatment was considered appropriate and the patient did not require additional therapies. She was subsequently assigned to clinical follow-up and is alive, with no evidence of the disease.

A secondary abdominal pregnancy with unusual placental implantation in the fallopian tube: a diagnostic challenge.

We reported a case of secondary abdominal pregnancy with placental implantation into the fallopian tube, diagnosed at 16 weeks, in a woman admitted to the emergency room complaining of syncopal attacks. The best approach would be termination of the pregnancy, taking into consideration the high risk to the mother and the low possibility of alive and healthy birth. We had to perform an urgent surgical intervention due to the fact that the patient was in a clinically unstable condition, which was related to hemoperitoneum. If placental implantation is on abdominal organs or vessel the best approach would be to ligate the cord and to leave placenta in situ. Taking into consideration the place of placental implant, the removal of the fallopian tube with the placenta was the safest approach in this case. The best and most acceptable form of treatment would be individualized in case of rare form of ectopic pregnancy.

A rare melanoma feature with primary ovarian origin: a case report and the literature review

Primary ovarian melanoma arising on a mature ovarian cystic teratoma is extremely rare. As best of our knowledge, to date, 49 cases have been reported in literature. Few information was reported about best management and therapy. We present a case occurred in a 69-year-old woman, without symptoms, who come to our unit for stress incontinence. A pelvic mass was detected and, after imaging evaluation, surgery was performed. The diagnosis was ovarian melanoma arose on a mature teratoma. No other adjuvant treatment was proposed after surgery. She died 9 months after the first diagnosis. Primary ovarian melanoma is a definite entity associated with a variable natural history and poor prognosis. Differential diagnosis is a challenge for the pathologist, because it must be differentiated by metastatic melanoma. The corner stone treatment of this disease is surgery; however, chemotherapy, immunotherapy, and target therapy seem to have a role.

Epstein-Barr virus in tumor-infiltrating B cells of myasthenia gravis thymoma: an innocent bystander or an autoimmunity mediator?

The thymus plays a key role in myasthenia gravis (MG), a B cell-mediated autoimmune disorder affecting neuromuscular junction. Most MG patients have thymic abnormalities, including hyperplasia and thymoma, a neoplasm of thymic epithelial cells. Epstein-Barr virus (EBV) is associated with autoimmune diseases and tumors. Recently, we showed EBV persistence and reactivation in hyperplastic MG thymuses, suggesting that EBV might contribute to intra-thymic B cell dysregulation in MG patients. Here, we investigated EBV involvement in thymoma-associated MG, by searching for EBV markers in MG (n=26) and non-MG (n=14) thymomas. EBV DNA and EBV-encoded small nuclear RNA (EBER) 1 transcript were detected in 14/26 (53.8%) and 22/26 (84.6%) MG thymomas, and only in 3 of 14 (21.4%) non-MG thymomas. Latent EBNA2 and late gp350/220 lytic transcripts were undetectable in all, but one, thymomas, and early lytic BZLF1 transcript was absent in all samples, suggesting that early infection events and EBV reactivation were very rare in thymomas. EBER1 and 2-positive cells were detected in MG, but not in non-MG, thymomas, as well as cells expressing EBV latency proteins (EBNA1, LMP1, LMP2A), that were mainly of B cell phenotype, indicating EBV association with MG rather than with thymoma. Toll-like receptor (TLR) 3 transcriptional levels were higher in MG than non-MG thymomas and positively correlated with EBER1 levels, suggesting a role for EBERs in TLR3 activation. Our findings show that EBV is commonly present in thymoma-infiltrating B cells of myasthenic patients, indicating a contribution of EBV to B cell-mediated autoreactivity in MG associated with thymic tumor.

Increased expression of Toll-like receptors 7 and 9 in myasthenia gravis thymus characterized by active Epstein-Barr virus infection.

Considerable data implicate the thymus as the main site of autosensitization to the acetylcholine receptor in myasthenia gravis (MG), a B-cell-mediated autoimmune disease affecting the neuromuscular junction. We recently demonstrated an active Epstein-Barr virus (EBV) infection in the thymus of MG patients, suggesting that EBV might contribute to the onset or maintenance of the autoimmune response within MG thymus, because of its ability to activate and immortalize autoreactive B cells. EBV has been reported to elicit and modulate Toll-like receptor (TLR) 7- and TLR9-mediated innate immune responses, which are known to favor B-cell dysfunction and autoimmunity. Aim of this study was to investigate whether EBV infection is associated with altered expression of TLR7 and TLR9 in MG thymus. By real-time PCR, we found that TLR7 and TLR9 mRNA levels were significantly higher in EBV-positive MG compared to EBV-negative normal thymuses. By confocal microscopy, high expression levels of TLR7 and TLR9 proteins were observed in B cells and plasma cells of MG thymic germinal centers (GCs) and lymphoid infiltrates, where the two receptors co-localized with EBV antigens. An increased frequency of Ki67-positive proliferating B cells was found in MG thymuses, where we also detected proliferating cells expressing TLR7, TLR9 and EBV antigens, thus supporting the idea that EBV-associated TLR7/9 signaling may promote abnormal B-cell activation and proliferation. Along with B cells and plasma cells, thymic epithelium, plasmacytoid dendritic cells and macrophages exhibited enhanced TLR7 and TLR9 expression in MG thymus; TLR7 was also increased in thymic myeloid dendritic cells and its transcriptional levels positively correlated with those of interferon (IFN)-ß. We suggested that TLR7/9 signaling may be involved in antiviral type I IFN production and long-term inflammation in EBV-infected MG thymuses. Our overall findings indicate that EBV-driven TLR7- and TLR9-mediated innate immune responses may participate in the intra-thymic pathogenesis of MG.

Innate immunity in myasthenia gravis thymus: pathogenic effects of Toll-like receptor 4 signaling on autoimmunity.

The thymus is the main site of immune sensitization to AChR in myasthenia gravis (MG). In our previous studies we demonstrated that Toll-like receptor (TLR) 4 is over-expressed in MG thymuses, suggesting its involvement in altering the thymic microenvironment and favoring autosensitization and autoimmunity maintenance processes, via an effect on local chemokine/cytokine network. Here, we investigated whether TLR4 signaling may favor abnormal cell recruitment in MG thymus via CCL17 and CCL22, two chemokines known to dictate immune cell trafficking in inflamed organs by binding CCR4. We also investigated whether TLR4 activation may contribute to immunodysregulation, via the production of Th17-related cytokines, known to alter effector T cell (Teff)/regulatory T cell (Treg) balance. We found that CCL17, CCL22 and CCR4 were expressed at higher levels in MG compared to normal thymuses. The two chemokines were mainly detected around medullary Hassall's corpuscles (HCs), co-localizing with TLR4(+) thymic epithelial cells (TECs) and CCR4(+) dendritic cells (DCs), that were present in higher number in MG thymuses compared to controls. TLR4 stimulation in MG TECs increased CCL17 and CCL22 expression and induced the production of Th17-related cytokines. Then, to study the effect of TLR4-stimulated TECs on immune cell interactions and Teff activation, we generated an in-vitro imaging model by co-culturing CD4(+) Th1/Th17 AChR-specific T cells, naïve CD4(+)CD25(+) Tregs, DCs and TECs from Lewis rats. We observed that TLR4 stimulation led to a more pronounced Teff activatory status, suggesting that TLR4 signaling in MG thymic milieu may affect cell-to-cell interactions, favoring autoreactive T-cell activation. Altogether our findings suggest a role for TLR4 signaling in driving DC recruitment in MG thymus via CCL17 and CCL22, and in generating an inflammatory response that might compromise Treg function, favoring autoreactive T-cell pathogenic responses.

Gela histological scoring system for post-treatment biopsies of patients with gastric MALT lymphoma is feasible and reliable in routine practice.

The International Extranodal Lymphoma Study Group (IELSG) promoted this study to determine the inter-observer agreement in the application of the Groupe d' Etude des Lymphomes de l' Adulte (GELA) histological scoring system for evaluating residual disease in post-treatment gastric biopsies of patients with gastric Mucosa-Associated Lymphoid Tissue (MALT) lymphoma (GML). Twenty-one patients with Helicobacter pylori -associated GML and treated with anti-H. pylori therapies were considered. A total of 154 biopsy sets from follow-up endoscopic procedures after H. pylori eradication were examined independently by seven pathologists from four European countries, following histological criteria suggested by the GELA scoring system. The overall concordance rate was 83% with a kappa value of 0·64, indicating a significant agreement among the seven observers. Most non-concordant responses clustered across the border of complete remission (CR) and probable minimal residual disease (pMRD), a distinction that does not imply critical clinical impact. Accordingly, when the analysis considered CR/pMRD as a single entity, the responses showed an overall concordance rate of 89% with kappa value of 0·83, thus indicating a high degree of inter-observer agreement. This study provides additional validation of the GELA histological grading system. This scheme can therefore be recommended in routine practice and deserves to be used in prospective clinical trials.

Inflammation and epstein-barr virus infection are common features of myasthenia gravis thymus: possible roles in pathogenesis.

The thymus plays a major role in myasthenia gravis (MG). Our recent finding of a persistent Epstein-Barr (EBV) virus infection in some MG thymuses, combined with data showing that the thymus is in a proinflammatory state in most patients, supports a viral contribution to the pathogenesis of MG. Aim of this study was to gain further evidence for intrathymic chronic inflammation and EBV infection in MG patients. Transcriptional profiling by low density array and real-time PCR showed overexpression of genes involved in inflammatory and immune response in MG thymuses. Real-time PCR for EBV genome, latent (EBER1, EBNA1, LMP1) and lytic (BZLF1) transcripts, and immunohistochemistry for LMP1 and BZLF1 proteins confirmed an active intrathymic EBV infection, further supporting the hypothesis that EBV might contribute to onset or perpetuation of the autoimmune response in MG. Altogether, our results support a role of inflammation and EBV infection as pathogenic features of MG thymus.

BDNF and its receptors in human myasthenic thymus: implications for cell fate in thymic pathology.

Here we show that in myasthenic thymus several cell types, including thymic epithelial cells (TEC) and immune cells, were the source and the target of the neurotrophic factor brain-derived growth factor (BDNF). Interestingly, many actively proliferating medullary thymocytes expressed the receptor TrkB in vivo in involuted thymus, while this population was lost in hyperplastic or neoplastic thymuses. Furthermore, in hyperplastic thymuses the robust coordinated expression of BDNF in the germinal centers together with the receptor p75NTR on all proliferating B cells strongly suggests that this factor regulates germinal center reaction. Finally, all TEC dying of apoptosis expressed BDNF receptors, indicating that this neurotrophin is involved in TEC turnover. In thymomas both BDNF production and receptor expression in TEC were strongly hindered. This may represent an attempt of tumour escape from cell death.

Chromosome instability and translocation t(11;18) in primary gastric marginal zone B-cell lymphoma of MALT-type.

The prognosis for patients with mucosa-associated lymphoid tissue (MALT) lymphomas is good; these tumours have usually an indolent course with overall survival rates that are greater than 80% at 5-year, but some rare cases with histological transformation in aggressive diffuse large cell lymphoma have also been diagnosed. Here, we present cytogenetic results on endoscopic bioptic material of 42 cases of primary gastric extranodal marginal zone B-cell lymphoma (EMZL) using fluorescence in situ hybridization (FISH) approach with API2, MALT1 and centromeric probes for chromosome 3 and 18, and their impact on the clinical outcome.

Primary nodal marginal zone B-cell lymphoma: clinical features and prognostic assessment of a rare disease.

This study defined the clinical features and assessed the prognosis of 47 patients (17 males, 30 females, median age 63 years) with primary nodal marginal zone B-cell lymphoma. Forty-five per cent had stage IV disease. Hepatitis C virus serology was positive in 24%. According to the Follicular Lymphoma International Prognostic Index (FLIPI), 33% were classified as low-risk, 34% as intermediate-risk, and 33% as high-risk. The 5-year overall survival (OS) was 69%. In univariate analysis worse OS was associated with: FLIPI (P = 0.02), age > 60 years (P = 0.05) and raised lactate dehydrogenase (P = 0.05). In multivariate analysis, only FLIPI predicted a worse OS (P = 0.02).

Marker expression in peripheral T-cell lymphoma: a proposed clinical-pathologic prognostic score.

PURPOSE: Although peripheral T-cell lymphoma, unspecified (PTCL/U), is the most common T-cell tumor in Western countries, no study to date has been based on the application of a wide panel of markers to a large series of patients and assessed the impact of phenotype on survival. We evaluated the expression of 19 markers in 148 PTCLs/U and 45 PTCLs of the angioimmunoblastic type (AILD). PATIENTS AND METHODS: The analysis was performed on tissue microarrays by immunohistochemistry and in situ hybridization. Clinical data were available in 93 PTCL/U patients, most of whom had been included in a previous study proposing a prognostic index (PIT). RESULTS: An aberrant phenotype with frequent loss of CD5 and/or CD7 was typical for PTCLs, irrespective of whether they were U or AILD. Aberrantly expressed proteins rarely included CD20, CD15, and CD30. Positivity for Epstein-Barr virus-associated small RNAs and CD15 expression emerged as adverse prognostic factors. Among PTCLs/U, the proliferation-associated protein Ki-67 turned out to be prognostically relevant and was integrated in a new predictive score, incorporating age (> 60 years), high lactate dehydrogenase, poor performance status, and Ki-67 > or = 80%. This score was associated with the patient outcome (P < .0001) and was found to be more robust than PIT (P = .0043) in the present series. CONCLUSION: Our retrospective analysis shows a wide range of protein expression in PTCLs and proposes a new prognostic index. The latter represents one of the first examples of mixed score (including patient- and tumor-specific factors) applied to malignant lymphomas and may be the basis for future prospective therapeutic trials.

Localized hypersensitivity and late coronary thrombosis secondary to a sirolimus-eluting stent: should we be cautious?

BACKGROUND: The US Food and Drug Administration recently issued a warning of subacute thrombosis and hypersensitivity reactions to sirolimus-eluting stents (Cypher). The cause and incidence of these events have not been determined. METHODS AND RESULTS: We present findings of a 58-year-old man who died of late stent thrombosis 18 months after receiving 2 Cypher stents for unstable angina. Although angiographic and intravascular ultrasound results at 8 months demonstrated the absence of neointimal formation, vessel enlargement was present. An autopsy showed aneurysmal dilation of the stented arterial segments with a severe localized hypersensitivity reaction consisting predominantly of T lymphocytes and eosinophils. CONCLUSIONS: The known pharmacokinetic elution profile of Cypher stents and the presence of polymer fragments surrounded by giant cells and eosinophils suggest that a reaction to the polymer may have caused late stent thrombosis. Careful long-term follow-up of patients with vessel enlargement after Cypher stent placement is recommended.

Drug-eluting versus bare metal coronary stents: long-term human pathology. Findings from different coronary arteries in the same patient.

A 71-year-old woman underwent right coronary artery (RCA) bare metal stenting during an acute myocardial infarction. Seven months later the patient received a sirolimus-eluting stent as treatment for an 80% left anterior descending coronary artery (LAD) stenosis. She remained asymptomatic until she presented with unstable angina 16 months later. Angiography demonstrated subtotal occlusion of the left obtuse marginal branch. The LAD sirolimus-eluting stent showed 0% stenosis. The RCA stent showed 30% restenosis. The left obtuse marginal branch lesion was successfully stented, but the patient suffered a fatal stroke 24 hours after the coronary intervention. At autopsy the 16-month-old LAD sirolimus-eluting stent was widely patent with a minute thrombus near the ostium of a small side branch. The stent surface appeared free of any other irregularities. Scanning light microscopy showed mild neointimal thickening. Scanning electron microscopy showed > 80% endothelialization of the stent. The 24-month-old RCA bare metal stent showed mild to moderate neointimal growth with > 90% endothelialization.

Immunoreactivity for cyclin D3 is frequently detectable in high-grade primary gastric lymphomas in the absence of the t(6;14)(p21.1;q32.3) chromosomal translocation.

Cyclin D3 plays a pivotal role in controlling the physiological progression from the G1 to the S phase of the cell cycle. Recent data suggest that cyclin D3 may be deregulated in extranodal non-Hodgkin's lymphomas (NHLs) as a consequence of the t(6;14)(p21.1;q32.3) translocation. The present study investigated for the first time by dual-colour fluorescence in situ hybridization (FISH) on interphase nuclei and immunohistochemistry the prevalence of the t(6;14) translocation and cyclin D3 immunoreactivity (IR) in a series of 29 stage I-IIE primary gastric NHLs (PGLs). No case showed the t(6;14) translocation. However, in five (17.2%) cases (two extranodal marginal zone lymphomas of MALT type, LGM; one diffuse large-cell lymphoma with a MALT component, DLCLM; and two diffuse large-cell lymphomas without a MALT component, DLCL), three to four cyclin D3 signals were detected by FISH. Co-hybridization with probes specific for the centromeric region and long arm of chromosome 6 indicated trisomy in one case (DLCL), whereas in the remaining four cases the pattern was highly suggestive of the presence of an isochromosome 6p. One (12.5%) case of LGM, six (75%) cases of DLCLM, and seven (53.8%) cases of DLCL (p = 0.0378) were immunoreactive for cyclin D3. Cyclin D3 IR was detected in two (40%) of the five cases with extra cyclin D3 signals and in 12 of the remaining 24 cases (50%, p = 1.000). These results suggest that the t(6;14) may represent a rare event in the pathogenesis of PGL and that cyclin D3 deregulation is most likely the result of epigenetic mechanisms.

Nongastric marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue.

A retrospective survey of patients with pathologically reviewed extragastric mucosa-associated lymphoma tissue (MALT) lymphomas from 20 institutions was performed. A total of 180 patients with histologically confirmed diagnosis of extragastric MALT lymphomas were studied. Their median age was 59 years (range, 21-92 years). Ann Arbor stage I disease was present in 115 patients (64%) and stage II disease in 16 (9%). Most cases were in the low or low-intermediate risk groups according to the International Prognostic Index (IPI). Forty-one (23%) patients had involvement of more than one extranodal site at diagnosis and in 24 cases (13%) the lymphoma presented at multiple mucosal sites (9 of them with only mucosal involvement, without bone marrow or nodal disease). Lymph node involvement was present in 21%. Patients were treated with a variety of therapeutic strategies, including chemotherapy in 78 cases. The median overall survival (OS) was not reached; the 5-year OS rate was 90% (95% CI, 82%-94%), the 5-year cause-specific survival (CSS) was 94% (95% CI, 87%-97%), and the 5-year progression-free survival (PFS) was 60% (95% CI, 50%-70%). Multivariate analysis showed that Ann Arbor stage was significantly associated with longer OS, nodal involvement with longer CSS, and favorable IPI score with better PFS. At a median follow-up of 3.4 years, 48 patients (27%; 95% CI, 20%-34%) had a relapse, 6 (3%; 95% CI, 1%-7%) showed histologic transformation, and 18 (10%; 95% CI, 6%-15%) experienced the development of a second tumor. Our data confirm the indolent nature of nongastric MALT lymphomas and the high rate of patients presenting with disseminated disease, which, when limited to mucosal sites, was not associated with a poorer outcome.

Lymphomas occurring late after solid-organ transplantation: influence of treatment on the clinical outcome.

BACKGROUND: Posttransplant lymphoproliferative disorders (PTLDs) that occur late after solid-organ transplantation are usually a monoclonal proliferation frequently characterized by the lack of the Epstein-Barr virus genome in tumor cells. The clinical outcome and the best management for patients who present with late PTLDs still remain unclear. PATIENTS AND METHODS: Thirty patients who developed PTLDs more than 12 months (range 13-156) after heart, kidney, or liver transplantation were retrospectively evaluated. Median age was 36.7 years (range 1-70). Fifty-five percent of patients presented with advanced-stage (III-IV) lymphoma, 43% of patients presented with B symptoms, and 40% of patients showed extranodal involvement. Twenty-four cases (75%) were categorized as monoclonal monomorphic PTLD. RESULTS: Three patients died of progressive multiorgan failure before any treatment was initiated. Overall, 17 (63%) patients obtained a clinical response (14 patients had complete remission [CR] and 3 patients had partial remission [PR]). Eight (47%) patients are still alive and in CR, two (12%) patients died in CR, and seven (41%) patients relapsed. With a median follow-up of 6 months (range 0.5-42.8), the median overall survival was 6.2 months. Both clinical response and survival were significantly influenced by the treatment. Indeed, all patients treated for limited disease with surgery or radiotherapy in combination with modulation of immunosuppression obtained CR and are still alive and in CR. On the contrary, 33% of patients who received chemotherapy obtained a clinical response, whereas 15% of patients who received chemotherapy showed progressive disease and 50% of patients who received chemotherapy died of toxicity (infectious or multiorgan failure). CONCLUSIONS: We suggest that patients with late PTLDs and limited disease may benefit from local treatment. For patients who require chemotherapy, we suggest that it should be administered to minimize the risk of infection complications.

The modified International Prognostic Index can predict the outcome of localized primary intestinal lymphoma of both extranodal marginal zone B-cell and diffuse large B-cell histologies.

We have previously reported on the efficacy of a modified International Prognostic Index (MIPI) in predicting the outcome of patients with primary gastric lymphoma. This prompted the retrospective analysis of a large series of patients with primary intestinal lymphoma (PIL) of both diffuse large B-cell (DLCL) and low-grade (extranodal marginal zone B-cell lymphoma, MZL) histology. Clinical records of 122 patients with localized primary intestinal lymphoma of MZL (n=35) and DLCL (n=87) histology, confirmed by an ad hoc expert panel of pathologists, were reviewed. Forty-nine patients were treated with single therapy, while 72 received combined-modality treatment, which included surgery followed by a short-term chemotherapy. MIPI was included in a multivariate prognostic analysis for overall survival (OS) and event-free survival (EFS). Sixty-five patients (75%) with DLCL and 22 with MZL(65%) achieved complete remission. After a median follow-up of 42 months (range 6-163 months), 5-year estimates of OS and EFS were 68% and 50% for DLCL and 65% and 26% for MZL. OS varied according to MIPI, from, respectively, 86% and 87% for DLCL and MZL patients with 0-1 risk factor to 50% and 32% for patients with > 1 risk factor (P=0.01 and P=0.02). Similar results were obtained for EFS. Cox regression analysis showed an unfavourable MIPI to be the only independent predictor of shorter EFS. This retrospective study shows that stage-MIPI can be a reliable prognostic indicator for PIL of both low-grade MZL and diffuse large B-cell histology, enabling the early identification of patients at higher risk of failure.