CD8+, CD56+ (natural killer-like) T-cell lymphoma involving the small intestine with no evidence of enteropathy: clinicopathology and molecular study of five Japanese patients

Monomorphic epitheliotropic intestinal T-cell lymphoma comprises morphologic and genomic heterogeneity impacting outcome

Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a rare aggressive T-cell lymphoma most reported in Asia. We performed a comprehensive clinical, pathological and genomic study of 71 European MEITL patients (36 males, 35 females, median age 67 years). The majority presented with gastrointestinal involvement and had emergency surgery, and 40% had stage IV disease. The tumors were morphologically classified into two groups: typical (58%) and atypical (i.e., non-monomorphic or with necrosis, angiotropism or starry-sky pattern) (42%), sharing a homogeneous immunophenotypic profile (CD3+ [98%] CD4- [94%] CD5- [97%] CD7+ [97%] CD8+ [90%] CD56+ [86%] CD103+ [80%] cytotoxic marker+ [98%]) with more frequent expression of TCRgd (50%) than TCRab (32%). MYC expression (30% of cases) partly reflecting MYC gene locus alterations, correlated with non-monomorphic cytology. Almost all cases (97%) harbored deleterious mutation(s) and/or deletion of the SETD2 gene and 90% had defective H3K36 trimethylation. Other frequently mutated genes were STAT5B (57%), JAK3 (50%), TP53 (35%), JAK1 (12.5%), BCOR and ATM (11%). Both TP53 mutations and MYC expression correlated with atypical morphology. The median overall survival (OS) of 63 patients (43/63 only received chemotherapy after initial surgery) was 7.8 months. Multivariate analysis found a strong negative impact on outcome of MYC expression, TP53 mutation, STAT5B mutation and poor performance status while aberrant B-cell marker expression (20% of cases) correlated with better survival. In conclusion, MEITL is an aggressive disease with resistance to conventional therapy, predominantly characterized by driver gene alterations deregulating histone methylation and JAK/STAT signaling and encompasses genetic and morphologic variants associated with very high clinical risk.

Targeted Next-generation Sequencing Reveals a Wide Morphologic and Immunophenotypic Spectrum of Monomorphic Epitheliotropic Intestinal T-Cell Lymphoma

Primary intestinal T-cell lymphoma (PITL) is highly aggressive and includes celiac disease-related enteropathy-associated T-cell lymphoma (EATL), monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), and primary intestinal peripheral T-cell lymphoma, not otherwise specified (ITCL-NOS). MEITL is the most common PITL in Asia, comprising of monomorphic medium-sized cells typically expressing CD8, CD56, and cytotoxic granules. Occasional cases with intermediate features between MEITL and ITCL-NOS are difficult to be classified and warrant further investigation. We collected 54 surgically resected PITLs from Taiwan, with 80% presenting with bowel perforation. The overall outcome was poor with a median survival of 7 months. Based on histopathology (monomorphic vs. pleomorphic) and immunophenotype, we classified these cases into 4 groups: MEITL with typical immunophenotype (n=34), MEITL with atypical immunophenotype (n=5), pleomorphic PITL with MEITL-like immunophenotype (n=6), and ITCL-NOS (n=9). There was no EATL in our cohort. Targeted next-generation sequencing of the first 3 groups showed highly prevalent loss-of-function mutations for SETD2 (85%, 80%, and 83%, respectively) and frequent activating mutations for STAT5B (64%, 60%, and 50%, respectively) and JAK3 (38%, 20%, and 50%, respectively). In contrast, ITCL-NOS cases had less frequent mutations of SETD2 (56%) and STAT5B (11%) and rare JAK3 mutations (11%). Our results suggest that there is a wider morphologic and immunophenotypic spectrum of MEITL as currently defined in the 2017 WHO classification. MEITL with atypical immunophenotype and PITL with MEITL-like immunophenotype shared clinicopathologic and molecular features similar to MEITL but distinct from ITCL-NOS, indicating that such cases may be considered as immunophenotypic or histopathologic variants of MEITL.

[Two Lethal Cases of Monomorphic Epitheliotropic Intestinal T-cell Lymphoma Deteriorated Rapidly After Emergency Surgery for Intestinal Perforation]

Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a rare and aggressive form of primary gastrointestinal T-cell lymphoma. Symptoms can vary but often include fever, abdominal pain, weight loss, diarrhea, obstruction, and perforation. Disease-specific symptoms rarely present before patients reach an advanced stage, which contributes to delayed diagnosis and poor survival outcomes. Approximately half of the patients with MEITL undergo emergency surgery for acute intestinal obstruction or perforation, leading to peritonitis, septic shock, and multiple organ failure. These factors contribute to treatment delays, which are associated with a worse prognosis, particularly in the case of chemotherapy. This paper reports two fatal cases of patients with MEITL who deteriorated rapidly after emergency surgery for intestinal perforation. Patient 1 complained of persistent diarrhea, but a delayed diagnosis led to bowel perforation, and the subsequent chemotherapy treatment was canceled. Patient 2 was diagnosed relatively early, but treatment was delayed due to intestinal perforation. Despite its rarity, MEITL should be considered through a "high index of suspicion" approach when a patient complains of unexplained abdominal pain and diarrhea. This is expected to improve early diagnosis and ultimately patient prognosis.

Lymphomatous effusion of monomorphic epitheliotropic intestinal T-cell lymphoma is characterized by azurophilic granules and is a dismal sign: Report of two new cases with literature review

Lymphoma involving serous effusion is uncommon. The diagnosis of effusion lymphoma may be challenging, particularly when the lymphoid cells are small to medium-sized, which would be difficult for differentiating reactive effusions from low grade lymphomas. Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is an uncommon type of aggressive intestinal T cell lymphoma with a median survival of 7 months. MEITL rarely disseminates to the body cavities. To date, there are only three reported cases of MEITL with malignant effusion. Here we report two additional cases of MEITL with lymphoma cells involving the pleural effusion and the ascites, respectively. Review of the three literature cases and our two new cases of MEITL with malignant effusion, cytoplasmic azurophilic granules were identified in both the two cases with Liu stain. The median survival time was 1.5 months after the occurrence of malignant effusion, even shorter than the median survival in patients with MEITL. Although the case number is small, malignant effusion seems to be a poor prognostic factor of MEITL.

Recent advances in intestinal lymphomas

A large variety of lymphoma types may develop as primary intestinal neoplasms in the small intestines or, less often, in the colorectum. Among these are a few entities such as enteropathy-associated T-cell lymphoma or immunoproliferative small intestinal disease that, essentially, do not arise elsewhere than in the gastrointestinal tract. In most instances the primary intestinal lymphomas belong to entities that also occur in lymph nodes or other mucosal sites, and may show some peculiar features. In the case of follicular lymphoma, important differences exist between the classical nodal cases and the intestinal cases, considered as a variant of the disease. It is likely that the local intestinal mucosal microenvironment is a determinant in influencing the pathobiological features of the disease. In this review we will present an update on the clinical, pathological and molecular features of the lymphoid neoplasms that most commonly involve the intestines, incorporating recent developments with respect to their pathobiology and classification. We will emphasize and discuss the major differential diagnostic problems encountered in practice, including the benign reactive or atypical lymphoid hyperplasias, indolent lymphoproliferative disorders of T or natural killer (NK) cells, and Epstein-Barr virus (EBV)-related lymphoproliferations.

Intestinal T-cell lymphomas: A retrospective analysis of 68 cases in China

AIM: To investigate the clinical features, diagnosis, treatment and prognosis of intestinal T-cell lymphomas (ITCL) by retrospective analysis.

METHODS: Sixty-eight patients who were diagnosed with ITCL in case reports in the Chinese literature were compiled and reviewed. Age, gender, CD56 expression, surgical management, multifocal nature, perforation and cyclophosphamide chemotherapy were analyzed as the prognostic factors. The Kaplan-Meier method was adopted for the univariate analysis and the cumulative survival curve analysis.

RESULTS: The male-to-female ratio was 1.52 to 1. The median age was 41.7 years. Twenty-seven patients had symptoms of abdominal pain or diarrhea. Thirty-six of 60 patients with temperature records had high fevers at the onset of the illness. Twenty-six of 34 patients who underwent fiberoptic colonoscopy were misdiagnosed with Crohn’s disease, intestinal tuberculosis or cancer. Sixty-one patients underwent surgery. Twelve of 61 surgical patients required a second operation for anastomotic leakage or secondary perforation. The sites of lesion involvement were the jejunum (8.82%), ileum (29.41%), ileum and colon (4.41%), colon (55.88%) and appendix (1.47%). The median cumulative survival rate was 3 mo (3.00 ± 0.48).

CONCLUSION: Efforts should be made to correctly diagnose ITCL and select the proper operative approach that may reduce serious complications and create opportunities for further treatment.

Pathobiology of T-cell and NK-cell lymphomas

T-cell and NK-cell lymphomas are uncommon lymphomas with an aggressive clinical course. The causes and precise cellular origins of most T-cell lymphomas are still not well defined. The WHO classification utilizes morphologic and immunophenotypic features in conjunction with clinical aspects and in some instances genetics to delineate a prognostically and therapeutically meaningful categorization. The anatomic localization of neoplastic T-cells and NK-cells parallels in part their proposed normal cellular counterparts and functions. T-cells of the adaptive immune system are mainly based in lymph nodes and peripheral blood, whereas lymphomas derived from T-cells and NK-cells of the innate immune system are mainly extranodal. This approach allows for better understanding of some of the manifestations of the T-cell and NK-cell lymphomas, including their cellular distribution, some aspects of morphology and even associated clinical findings.

Type II EATL (epitheliotropic intestinal T-cell lymphoma): a neoplasm of intra-epithelial T-cells with predominant CD8αα phenotype

In this multicentre study, we examined 60 cases of Type II enteropathy-associated T-cell lymphoma (EATL) from the Asia-Pacific region by histological review, immunohistochemistry and molecular techniques. Patients were mostly adult males (median age: 58 years, male:female 2.6:1), presenting with abdominal pain (60%), intestinal perforation (40%) and weight loss (28%). None had a history of coeliac disease and the median survival was only 7 months. Histologically, these tumours could be divided into (i) central tumour zone comprising a monotonous population of neoplastic lymphocytes, (ii) peripheral zone featuring stunted villi and morphologically atypical lymphocytes showing epitheliotropism, and (iii) distant mucosa with normal villous architecture and cytologically normal intra-epithelial lymphocytes (IELs). Characterized by extensive nuclear expression of Megakaryocyte-associated tyrosine kinase (MATK) (87%) and usually a CD8(+)CD56(+) (88%) cytotoxic phenotype, there was frequent aberrant expression of CD20 (24%). T-cell receptor (TCR) expression was silent or not evaluable in 40% but of the remainder, there was predominant expression of TCRαβ over TCRγδ (1.6:1). In keeping with the normal ratio of IEL subsets, CD8(+) cases showed predominant CD8αα homodimer expression (77%), regardless of TCR lineage. These tumours constitute a distinct entity from classical EATL, and the pathology may reflect tumour progression from IEL precursors, remnants of which are often seen in the distant mucosa.

Type II enteropathy-associated T-cell lymphoma: a multicenter analysis from the Asia Lymphoma Study Group

Enteropathy-associated T-cell lymphoma (EATL) is a rare primary gastrointestinal T-cell lymphoma. A multicenter study from the Asia Lymphoma Study Group identified 38 EATL patients within a 19-year period. All cases were type II EATL. Men were affected twice as common as women, at a median age of 59 (23-89) years. None had a history of celiac disease. The sites of involvement were small bowel and stomach (5%), small bowel (63%), small and large bowel (16%), and large bowel (18%). Common presenting features were bowel perforation (34%), pain (32%), and obstruction (21%). Lymphomas showed monomorphic neoplastic lymphoid infiltrates that were CD3⁺ (100%), CD56⁺ (91%), TIA-1⁺ (96%), CD4⁻CD8⁺ (63%), CD4⁺CD8⁺ (19%), CD4⁻CD8⁻ (16%), and CD4⁺CD8⁻ (3%). Epstein Barr virus was demonstrable in three cases. Despite chemotherapy and/or surgical resection, the overall response and complete response rates were poor at 46% and 38%. The median overall survival (OS) was 7 months and progression-free-survival (PFS) 1 month. Five patients underwent hematopoietic stem cell transplantation all were alive. Age and the prognostic index for peripheral T-cell lymphoma were not prognostically significant. Good performance status was associated with better OS (P = 0.03), and response to initial treatment led to better OS and PFS (P < 0.001).

Extranodal NK/T-cell lymphoma, nasal type, includes cases of natural killer cell and αβ, γδ, and αβ/γδ T-cell origin: a comprehensive clinicopathologic and phenotypic study

Extranodal NK/T-cell lymphoma (ENKTL), nasal type, may be of NK or T-cell origin; however, the proportion of T-ENKTLs and whether they are of αβ or γδ type remains uncertain. To elucidate the cell of origin and detailed phenotype of ENKTL and assess any clinicopathologic associations, 67 cases of ENKTL from Thailand were investigated, together with 5 γδ enteropathy-associated T-cell lymphomas (EATLs) for comparison. In all, 70% of the ENKTL were T-cell receptor (TCR) β,γ and, in cases tested, δ negative (presumptive NK origin); 5% were TCR γδ, 3% were TCR αβ, 1% were TCR αβ/γδ, and 21% were indeterminate. Out of 17 presumptive NK-ENKTLs tested, 3 had clonal TCR rearrangements. All cases were EBV and TIA-1; >85% were positive for CD3, CD2, granzyme B, pSTAT3, and Lsk/MATK; and all were CD16. Presumptive NK-ENKTLs had significantly more frequent CD56 (83% vs. 33%) and CXCL13 (59% vs. 0%) but less frequent PD-1 (0% vs. 40%) compared with T-ENKTLs. Of the NK-ENKTLs, 38% were Oct-2 compared with 0% of T-ENKTLs, and 54% were IRF4/MUM1 compared with 20% of T-ENKTLs. Only αβ T-ENKTLs were CD5. Intestinal ENKTLs were EBV and had significantly more frequent CD30, pSTAT3, and IRF4/MUM1 expression but less frequent CD16 compared with γδ EATL. Significant adverse prognostic indicators included a primary non-upper aerodigestive tract site, high stage, bone marrow involvement, International Prognostic Index ≥2, lack of radiotherapy, Ki67 >40%, and CD25 expression. The upper aerodigestive tract ENKTLs of T-cell origin compared with those of presumptive NK origin showed a trend for better survival. Thus, at least 11% of evaluable ENKTLs are of T-cell origin. Although T-ENKTLs have phenotypic and some possible clinical differences, they share many similarities with ENKTLs that lack TCR expression and are distinct from intestinal γδ EATL.

An algorithmic approach to the diagnosis of NK and T cell lymphomas

Lymphomas of natural killer (NK) and T cell lineages are uncommon disorders, although as a group they are more usually encountered in Asia compared to Western populations. In part due to their rarity, diagnosis and classification of T cell lymphomas often pose a challenge to clinicians and pathologists. Although there are morphological features that are characteristic of certain subtypes, correct classification of NK and T cell neoplasms relies heavily on the immunophenotype. With few exceptions, non-random genetic alterations such as translocations are less often seen in T cell neoplasms, adding to the diagnostic difficulty. Given these limitations, pathological diagnosis and classification of NK and T cell lymphomas are anything but straightforward. This paper attempts to present a practical algorithmic approach for the general pathologist who is confronted with these neoplasms.

Type II enteropathy-associated T-cell lymphoma: a distinct aggressive lymphoma with frequent γδ T-cell receptor expression

Enteropathy-associated T-cell lymphoma (EATL), an uncommon lymphoma of intestinal intraepithelial T lymphocytes, occurs with a higher frequency in northern Europe due to association with celiac disease. Data on the occurrence of EATL in the Asian population, among whom celiac disease is very rare, are conflicting. This study aimed to characterize EATL encountered in the Chinese population in Hong Kong. Eighteen cases were identified, all fulfilling the criteria of type II rather than classical EATL. The patients, including 13 men and 5 women, had a median age of 62 years. Most presented with small bowel perforation, and there was no history of malabsorption. The clinical course was aggressive, with 14 of 16 patients dying of progressive disease or complications, usually within 1 year. The histologic features were practically identical in all cases. The central zone of the tumor showed ulceration with or without perforation and was characterized by monotonous transmural infiltration of the bowel by small-sized or medium-sized lymphoma cells with few admixed inflammatory cells and no coagulative necrosis. The peripheral zone featured lateral spread of lymphoma cells in the mucosa, accompanied by variable involvement of the submucosa and muscularis. In all cases, there was an intraepithelial lymphocytosis zone contiguous or discontinuous with the peripheral zone, which was characterized by infiltration of the intestinal epithelium by nonatypical small lymphocytes, and not accompanied by other histologic changes of enteropathy. The most common phenotype of the lymphoma cells was CD3+, CD5-, CD4-, CD8+, CD56+, TIA1+, CD30-, and Epstein-Barr virus, and 2 cases showed aberrant expression of CD20. A remarkable finding was that 14 (78%) cases expressed γδ T-cell receptor, and only 6 (33%) expressed αβ T-cell receptor (with 3 cases coexpressing both T-cell receptors and 1 case expressing neither). The immunophenotype of the intraepithelial lymphocytes was either discordant (particularly with respect to CD8 and CD56 expressions) or concordant with the lymphoma cells of the corresponding cases. Thus, this study shows that EATL occurring in the Chinese population is exclusively of type II. In contrast to several studies, intraepithelial lymphocytosis can be consistently demonstrated and this component seems to represent a precursor lesion of EATL rather than a manifestation of celiac disease. In view of the differences in epidemiology and clinicopathologic features, we believe it is justified to separate out type II EATL from the EATL category as a distinct form of lymphoma, for which we propose the designation "monomorphic intestinal T-cell lymphoma."

Nonhepatosplenic γδ T-cell lymphomas represent a spectrum of aggressive cytotoxic T-cell lymphomas with a mainly extranodal presentation

γδ T cells represent a minor T-cell subset that is mainly distributed in mucosal surfaces. Two distinct lymphomas derived from these cells have been recognized: hepatosplenic γδ T-cell lymphoma (HSTL) and primary cutaneous γδ T-cell lymphoma (PCGD-TCL). However, whether other anatomic sites may also be involved and whether they represent a spectrum of the same disease are not well studied. The lack of T-cell receptor (TCR)β expression has been used to infer a γδ origin when other methods are not available. We studied 35 T-cell tumors suspected to be γδ TCL using monoclonal antibodies reactive with TCR δ or γ in paraffin sections. We were able to confirm γδ chain expression in 22 of 35 cases. We identified 8 PCGD-TCLs, 6 HSTLs, and 8 γδ TCLs without hepatosplenic or cutaneous involvement involving mainly extranodal sites. Two such cases were classified as enteropathy-associated T-cell lymphoma, type II. The other γδ TCL presented in the intestine, lung, tongue, orbit, and lymph node. In addition, we observed 13 cases with mainly extranodal involvement that lacked any TCR expression ("TCR silent"). In all cases, a natural killer cell origin was excluded. In conclusion, the lack of TCRβ expression does not always predict γδ-T-cell derivation, as TCR silent cases may be found. The recognition of γδ TCL presenting in extranodal sites other than skin and liver/spleen expands the clinical spectrum of these tumors. However, non-HSTL γδ TCL do not seem to represent a single entity. The relationship of these tumors with either HSTL or PCGD-TCL requires further study.

Primary intestinal T-cell and NK-cell lymphomas: a clinicopathological and molecular study from China focused on type II enteropathy-associated T-cell lymphoma and primary intestinal NK-cell lymphoma

In China, which is a non-endemic area for celiac disease, primary intestinal T-cell and NK-cell lymphomas might comprise heterogeneous subtypes. Both type II enteropathy-associated T-cell lymphoma and primary intestinal NK-cell lymphoma are rarely reported and poorly characterized in China. In this study, we examined the clinicopathological and molecular features of 38 cases of primary intestinal T-cell and NK-cell lymphoma in Chinese patients. Based on these findings, we first classified the patients into an NK-cell group (n=6) and a T-cell group (n=32). In the NK-cell group, the mean age was 37 years. All tumors of the NK-cell group were positive for Epstein-Barr virus encoded mRNA in the majority of tumor cells and were polyclonal according to the results of commercial BIOMED-2 T-cell receptor gene rearrangement assays. The survival in the NK-cell group was significantly worse than that of the T-cell group (P=0.0247). Next, 7 tumors of the T-cell group were considered type II enteropathy-associated T-cell lymphoma, while 24 were considered peripheral T-cell lymphoma, not otherwise specified (NOS). In the type II enteropathy-associated T-cell lymphoma group, the mean age was 55 years. Type II enteropathy-associated T-cell lymphoma tumor cells from all seven patients were monomorphic, medium sized. The survival in the type II enteropathy-associated T-cell lymphoma group was significantly worse than that of the peripheral T-cell lymphoma, NOS group (P=0.0181). Multivariate analysis identified NK-cell phenotype, male gender, and CD8 positivity as factors for poor prognosis in our series of primary intestinal T-cell and NK-cell lymphoma patients. In conclusion, most cases of primary intestinal T-cell and NK-cell lymphoma in China are not associated with celiac disease and could be classified to NK-cell group, type II enteropathy-associated T-cell lymphoma group, and peripheral T-cell lymphoma, NOS group. Each group has distinctive histopathological features with prognostic significance.

Enteropathy-associated T-cell lymphoma: clinical and histological findings from the international peripheral T-cell lymphoma project

Few large, international series of enteropathy-associated T-cell lymphoma (EATL) have been reported. We studied a cohort of 62 patients with EATL among 1153 patients with peripheral T-cell or natural killer (NK)-cell lymphoma from 22 centers worldwide. The diagnosis was made by a consensus panel of 4 expert hematopathologists using World Health Organization (WHO) criteria. Clinical correlations and survival analyses were performed. EATL comprised 5.4% of all lymphomas in the study and was most common in Europe (9.1%), followed by North America (5.8%) and Asia (1.9%). EATL type 1 was more common (66%) than type 2 (34%), and was especially frequent in Europe (79%). A clinical diagnosis of celiac sprue was made in 32.2% of the patients and was associated with both EATL type 1 and type 2. The median overall survival was only 10 months, and the median failure-free survival was only 6 months. The International Prognostic Index (IPI) was not as good a predictor of survival as the Prognostic Index for Peripheral T-Cell Lymphoma (PIT). Clinical sprue predicted for adverse survival independently of the PIT. Neither EATL subtype nor other biologic parameters accurately predicted survival. Our study confirms the poor prognosis of patients with EATL and the need for improved treatment options.

Pathological and immunohistological findings and genetic aberrations of intestinal enteropathy-associated T cell lymphoma in Japan

AIMS

To elucidate the clinicopathological findings of primary intestinal enteropathy-associated T cell lymphoma (EATL) in Japan, a non-endemic area for coeliac disease.

METHODS AND RESULTS

Of the 24 cases, four (17%) had large-cell lymphoma (type I), and the remaining 20 (83%) had medium-sized lymphoma (type II). Lymphoma cells of the three type I cases were CD56-positive. Only one (4%) case showed typical CD56- and CD8-negative and CD30-positive type I EATL. In type II EATL, lymphoma cells of the 16 (80%) and 11 (55%) cases were positive for CD56 and CD8, respectively. Intramucosal tumour spreading and adjacent enteropathy-like lesions were detected in 15 (71%) and 16 (76%) of 21 cases, with a severe increase of intraepithelial lymphocytes (IELs) in 12 (57%). IELs of enteropathy-like lesions in five (24%) cases expressed T-bet, with no cases of CD30-positive IELs. Characteristic findings from comparative genomic hybridization of 15 cases indicated gains of 8q2 (47%), Xp (53%) and Xq (73%), but no gain of 9q3. Regarding, human leucocyte antigen (HLA) status, six cases examined did not express the DQB1*02 allele.

CONCLUSIONS

Japanese EATL exhibited different histology, cytogenetic findings and HLA status from those of typical type I EATL. The rare incidence of coeliac disease may influence the tumour cell characteristics of EATL and IELs.

Primary small intestinal natural killer/T cell lymphoma mimicking tuberculous peritonitis: report of a case and review of the literature

Extranodal natural killer/T cell lymphoma is very rarely encountered in clinical practice. It has a high mortality rate and very short median survival. Early diagnosis of these rare tumors, especially those originating from the small intestine, is usually difficult because of its nonspecific symptoms. Herein, we describe a case of a primary small intestinal natural killer/T cell lymphoma in a 52-year-old man who presented with abdominal fullness and weight loss. The clinical symptoms, elevation of serum levels of cancer antigen-125, and presence of ascites initially led to the suspicion of tuberculous peritonitis. Abdominal computed tomography scan demonstrated a hypodense tumor in the jejunum. Finally, the tumor was surgically confirmed to be a natural killer/T-cell lymphoma. Although aggressive chemotherapy was prescribed, the patient subsequently died of disease progression. In addition, we also review the English literature on this rare disease.

Enteropathy associated T-cell lymphoma and its precursor lesions

Enteropathy Associated T-cell Lymphoma (EATL) is an intestinal tumour of intra-epithelial lymphocytes. Based on morphology, immunohistochemistry and genetic profile EATL can be divided into two groups. EATL type I is a large cell lymphoma which is highly associated with Coeliac Disease (CD) and mostly presents with malabsorption, weight loss and CD-related symptoms. EATL type II consists of small to medium-sized cells and presents often with obstruction or perforation of the small bowel. This type of EATL has no known association with CD. When EATL has been diagnosed a thorough diagnostic work-up is needed. This work-up preferably includes video capsule enteroscopy (VCE), double-balloon enteroscopy (DBE), computed tomography (CT) combined with 18F-fluorodeoxyglucose positron emission tomography scan (18F-FDG-PET scan) if possible and magnetic resonance enteroclysis (MRE). Nowadays, most EATL patients are treated with chemotherapy mostly preceded by resection of the tumour and followed by stem cell transplantation. Despite these therapies outcome of EATL remains very poor with a 5-year survival of 8-20%. In order to improve survival prospective multicentre trials, studying new therapies are needed. The combination of chemotherapy, monoclonal antibodies and/or apoptosis inducing small molecules might be a potential treatment for EATL in the (nearby) future.

NK-cell lineage predicts poor survival in primary intestinal NK-cell and T-cell lymphomas

Most primary intestinal natural killer (NK)-cell and T-cell lymphomas (PINKTL) in the Northern Europe are enteropathy-associated T-cell lymphomas, a complication of celiac disease, which is rare in the East. Primary intestinal NK-cell lymphoma is extremely rare and is poorly characterized. We investigated 30 cases of PINKTL from Taiwan with male: female at 2:1, median age at 55.5, 80% with jejunal/ileal involvement, 77% with perforation, 27% with multicentric tumors, and 67% at stage IE. All 7 cases tested for serum IgA anti-tissue transglutaminase were negative. Only 3 (10%) tumors showed enteropathy. Six (20%) were NK-cell lymphoma and 24 (80%) were T-cell lymphoma. The tumor cells in 21/30 (70%) cases were small to medium sized, which correlated with the coexpression of both CD8 and CD56. All tumors expressed at least 1 cytotoxic marker. All 6 NK-cell lymphomas were negative for betaF1, diffusely positive for Epstein-Barr virus-encoded mRNA (EBER), and polyclonal for T-cell receptor gene rearrangement. Five (22%) of the 24 T-cell tumors expressed betaF1, 8 (35%) of the 23 tumors were positive for EBER, and 20 (95%) of the 21 tumors were clonal for T-cell receptor. The overall 1-year survival was 36%. Univariate regression analysis showed that NK-cell lineage, multicentricity, and perforation were associated with poor prognosis. NK-cell lineage (P=0.037) was a poor prognostic factor by multivariate Cox proportional hazard regression analysis. PINKTL in Taiwan is predominantly not enteropathic with a high frequency of perforation, small to medium tumor cell size and cytotoxic phenotype. Primary intestinal NK-cell lymphoma carries a very poor prognosis, and is probably a distinct entity.