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

Primary intestinal T-cell and natural killer-cell lymphomas: Clinicopathologic and prognostic features of 79 cases in South China

OBJECTIVES

Primary intestinal T-cell and natural killer-cell lymphomas (PITNKLs) are aggressive and make pathologic diagnoses in biopsy specimens challenging. We analyzed different subtypes' clinicopathologic features and treatment outcomes.

METHODS

Seventy-nine PITNKL cases were characterized by clinical, morphologic, and immunohistochemical features.

RESULTS

Among 79 cases of PITNKLs from 2008 to 2017 in our institution, 40 (50.63%) were extranodal NK/T-cell lymphoma, nasal type (ENKTL); 32 (40.51%) monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL); 6 (7.59%) intestinal T-cell lymphoma, not otherwise specified; and 1 (1.27%) indolent T-cell lymphoma of the gastrointestinal tract. Small intestine (n = 47) was the most common site. Monomorphic epitheliotropic intestinal T-cell lymphoma showed distinctive clinicopathologic features from other subtypes with high expression (96.88%) of spleen tyrosine kinase (SYK) and PD-L1 (87.5%) and the poorest prognosis (P < .001). CD30 was highly expressed in ENKTL (9/17, 57.94%) and irrelevant to prognosis (P > .05).

CONCLUSIONS

Cases of PITNKL are biologically heterogeneous; most have a dismal prognosis. SYK and PD-L1 expression might be a significant marker for MEITL and helps differential diagnosis.

Clinical and Histopathological Features of an Italian Monocentric Series of Primary Small Bowel T-Cell Lymphomas

The gastrointestinal (GI) tract is the most common extranodal site of occurrence of non-Hodgkin lymphomas. Most GI lymphomas are of B-cell lineage, while T-cell lymphomas are less frequent. The aim of our retrospective study was to depict the clinical-pathological profile of a series of patients affected by intestinal T-cell lymphomas (ITCL) and possibly define hallmarks of these neoplasms. A total of 28 patients were included: 17 enteropathy-associated T-cell lymphomas (EATL), 5 monomorphic epitheliotropic T-cell lymphomas (MEITL), 3 indolent T-cell lymphoproliferative disorders of the gastrointestinal tract (ITCLDGT), and 3 intestinal T-cell lymphomas not otherwise specified (ITCL-NOS). Celiac disease (CD) was diagnosed in around 70% of cases. Diagnosis of EATL showed a significant correlation with CD30 expression, whereas MEITL with angiotropism and CD56 positivity. ITCLDGT cases showed plasma cells infiltration. Peripheral lymphocytosis, the absence of a previous diagnosis of CD, an advanced Lugano clinical stage, and the histological subtype ITCL-NOS were significantly associated with worse survival at multivariate analysis. Our findings about the epidemiological, clinical, and histopathological features of ITCL were in line with the current knowledge. Reliable prognostic tools for these neoplasms are still lacking but according to our results lymphocytosis, diagnosis of CD, Lugano clinical stage, and histological subtype should be considered for patient stratification.

Proteomics and genomics of a monomorphic epitheliotropic intestinal T-cell lymphoma: An extremely rare case report and short review of literature

RATIONALE

Monomorphic epitheliotropic intestinal T-cell lymphoma, formerly known as enteropathy-associated T-cell lymphoma, is an extremely rare, aggressive peripheral extranodal T-cell lymphoma, that is infrequent in native European and Caucasian populations. The current study presents the clinicopathological features, diagnostic approach, and clinical outcomes of this rare entity of lymphoma and highlights the importance of the early diagnosis of monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL).

PATIENT CONCERNS

Main symptoms and/or important clinical findings: We present the case of a 69-year-old male patient presenting with an abdominal mass, intestinal transit disorder, and weight loss. The abdominal computed tomography (CT) revealed features suggestive of a malignancy. Following clinical and imaging investigations, surgical resection of the small intestine with other areas of involvement has been performed and further to the histopathological examination and immunohistochemical testing are mandatory.

DIAGNOSES AND INTERVENTIONS

Histopathological evaluation of the tumor revealed a proliferation of medium- to large-sized monomorphic lymphocytes, with vesicular nuclei, prominent nucleoli, and a moderate amount of clear to pale eosinophilic cytoplasm, with an association of infrequent Reed-Sternberg-like cells. Immunohistochemical assessment of the aforementioned tumor using CD3, CD8, CD5, CD20, and CD30 confirmed the T cell proliferation line and the monomorphic epitheliotropic intestinal T-cell lymphoma diagnosis.

LESSONS

The current report highlights the importance of early diagnosis of MEITL owing to its poor prognosis and presents histopathological features that help distinguish MEITL from inflammatory bowel diseases and less aggressive T-cell lymphomas.

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.

Cellular Origins and Pathogenesis of Gastrointestinal NK- and T-Cell Lymphoproliferative Disorders

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.

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.

Monomorphic epitheliotropic intestinal T-cell lymphoma presenting as melena with long-term survival: A case report and review of literature

BACKGROUND

Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is a rare primary intestinal T-cell lymphoma, previously known as enteropathy-associated T-cell lymphoma type II. MEITL is an aggressive T-cell lymphoma with a poor prognosis and high mortality rate. The known major complications of MEITL are intestinal perforation and obstruction. Here, we present a case of MEITL that was diagnosed following upper gastrointestinal bleeding from an ulcerative duodenal lesion, with recurrence-free survival for 5 years.

CASE SUMMARY

A 68-year-old female was admitted to our hospital with melena and mild anemia. An urgent esophagogastroduodenoscopy (EGD) revealed bleeding from an ulcerative lesion in the transverse part of the duodenum, for which hemostatic treatment was performed. MEITL was diagnosed following repeated biopsies of the lesion, and cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) chemotherapy was administered. She achieved complete remission after eight full cycles of CHOP therapy. At the last follow-up examination, EGD revealed a scarred ulcer and ¹⁸Fluorodeoxyglucose (¹⁸FDG) positron emission tomography/computed tomography showed no abnormal FDG accumulation. The patient has been in complete remission for 68 mo after initial diagnosis.

CONCLUSION

To rule out MEITL, it is important to carefully perform histological examination when bleeding from a duodenal ulcer is observed.

Monomorphic Epitheliotropic Intestinal T-cell Lymphoma of the Stomach: Two Case Reports and a Literature Review

We describe the clinicopathologic and molecular features of 2 cases of gastric monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), which were first diagnosed from gastric biopsies, one was primary whereas the other was gastric involvement by MEITL. Both cases were older men with stomach ulcers. Case 1 was admitted for a hemorrhage in the upper digestive tract and case 2 for edema. Histology of both cases showed infiltrated monomorphic and medium-sized lymphocytes with lymphoid epithelial phenomenon. An inflammatory background and vascular hyperplasia were also observed likely due to the ulceration. Neoplastic cells expressed CD2, CD3, CD7, CD8, CD56, TIA-1, and MYC, not CD5, CD4, Granzyme B, CD20, CD30, TdT, or EBER. Both lymphomas showed TCRG gene rearrangement and c-MYC gains. Moreover, we first affirmed polysomy of chromosome 8 in case 2. For correct diagnosis of this rare tumor at the rare location, it is important that pathologists raise the possibility and exclude other differential diagnoses.

A case of celiac disease with type I enteropathy-associated T-cell lymphoma in a Japanese male patient

A 45-year-old Japanese male patient who was diagnosed with celiac disease (CeD) developed type I enteropathy-associated T-cell lymphoma (EATL). In 2013, the patient was admitted to our hospital with worsening of diarrhea and weight loss. Pathological examination of biopsy specimens from the duodenum and ileum led to a diagnosis of suspected EATL. A previous total colonoscopy (TCS) indicated villous atrophy in the terminal ileum. The patient was changed to a gluten-free diet, and the nutritional status gradually improved. In September 2014, he experienced acute right lower abdominal pain. He underwent urgent surgery, and a perforation was identified in the ileum. A diagnosis of type I EATL was made following histopathological examination. After eight courses of CHOP therapy, the patient entered complete remission. TCS and esophagogastroduodenoscopy with magnifying narrow-band imaging performed in 2015 identified villous regrowth in the distal ileum and duodenum. Capsule endoscopy also found villous regrowth in the entire small intestine. To our knowledge, this is the first case of type I EATL following CeD with villous atrophy before EATL occurrence in a Japanese HLA-DQ2 carrier. The possibility of type I EATL occurring after CeD should be recognized, although CeD is quite rare in Japan.

Endoscopic and clinicopathological characteristics of gastrointestinal adult T-cell leukemia/lymphoma

Background

Adult T-cell leukemia/lymphoma (ATLL) frequently involves the gastrointestinal (GI) tract, and patients mainly show an aggressive clinical course despite of intensive cytotoxic treatments. We investigated the characteristic clinicopathological and endoscopic features of GI ATLL.

Methods

This was a retrospective analysis of 61 GI tract lesions in 54 ATLL patients.

Results

Thirty-six (67%) patients were classified as having lymphoma-type ATLL and 18 (33%) patients were classified as having acute-type with leukemic changes. Examined ATLL lesions in the stomach and intestine (small intestine and colorectum) were 40 (66%) and 21 (34%), respectively. Gastric ATLL lesions were frequently found in the lymphoma-type (29/38; 76%) compared with the acute-type lesions (11/23; 48%; P=0.023). Intestinal ATLL lesions were frequent in the acute-type (12/23; 52%) compared with the lymphoma-type lesions (9/38; 24%; P=0.023). Endoscopically, tumor-forming type lesions were significantly more frequent in lymphoma-type ATLL lesions (29/38 lesions; 76%) compared with acute-type lesions (10/23; 44%; P=0.0096). The superficial spreading-type was significantly more frequent in acute-type lesions (12/23 lesions; 52%) compared with lymphoma-type lesions (3/38; 8%; P=0.0003). Additionally, gastropathy-, enteropathy-, or proctocolitis-like lesions were distinct features, mainly in the acute type (9/23 lesions; 39%). Twenty three of 39 tumor-forming-type lesions (59%) were significantly composed of pleomorphic or anaplastic large cell lymphoma, and 13 of 15 superficial spreading-type lesions (87%) were significantly composed of pleomorphic medium-sized cells (P=0.007, in each). Six patients (11%) who were estimated as having primary GI ATLL based on restricted clinical stages, showed a significantly better overall survival (OS) compared with the 48 advanced-stage patients (P=0.017). Twenty patients with solitary tumor-forming-type lesions showed a significantly better OS than 17 patients with the multiple tumor-forming-type (P=0.015) and five with the mucosal-thickening-type lesions (P=0.04). Twenty-six patients with pleomorphic or anaplastic large cell ATLL showed a significantly better prognosis compared with 28 patients with pleomorphic medium-sized ATLL (P=0.034).

Conclusions

ATLL predominantly involves the stomach. Leukemic behavior of ATLL had a large influence on the tumor location and endoscopic features of GI tract lesions. Gastropathy-, enteropathy-, and proctocolitis-like lesions showed additional distinct characteristics. Primary GI ATLL in the early clinical stages, solitary tumor-forming-type lesions and large tumor cells showed better prognostic factors than other factors, respectively.

Two cases of monomorphic epitheliotropic intestinal T-cell lymphoma associated with coeliac disease

Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) is an aggressive type of intestinal lymphoma which affects individuals without evidence of enteropathy. In this single-centre case series, we describe the first two cases of MEITL in Caucasian patients suffering from histologically-proven coeliac disease (CD). Original medical records were retrieved and anonymised. All biopsy and surgical MEITL specimens were reviewed by three haematopathologists. Two patients aged 63- and 55-year old at CD diagnosis, subsequently developed a MEITL. MEITL always involved the ileum and was multifocal. Both patients died from complications after surgery, including gastrointestinal bleeding, septic shock and multiorgan failure, with a mean survival since MEITL diagnosis of 15.5 ± 16.3 months. In one case, array-CGH revealed a large deletion on chromosome nine between 9p13.1 and 9p24.1, and a recurrent chromosome gain at 9q33-q34. Our cases indicate that a subset of MEITL may arise in Caucasian patients suffering from CD. The clinical, pathological and molecular features of these cases show a partial overlap with enteropathy-associated T-cell lymphoma.

SYK expression in monomorphic epitheliotropic intestinal T-cell lymphoma

Monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), formerly known as type II enteropathy associated T-cell lymphoma (type II EATL), is a rare, aggressive primary intestinal T-cell lymphoma with a poor prognosis and an incompletely understood pathogenesis. We collected 40 cases of MEITL and 27 cases of EATL, formerly known as type I EATL, and comparatively investigated the T-cell receptor (TCR) itself and associated signaling molecules using immunohistochemistry, amplicon deep sequencing and bisulfite pyrosequencing. The TCR showed both an αβ-T-cell origin (30%) and a γδ-T-cell derivation (55%) resulting in a predominant positive TCR phenotype in MEITL compared with the mainly silent TCR phenotype in EATL (65%). The immunohistochemical expression of the spleen tyrosine kinase (SYK) turned out to be a distinctive feature of MEITL (95%) compared with EATL (0%). Aberrant SYK overexpression in MEITL is likely caused by hypomethylation of the SYK promoter, while no common mutations in the SYK gene or in its promoter could be detected. Using amplicon deep sequencing, mutations in DNMT3A, IDH2, and TET2 were infrequent events in MEITL and EATL. Immunohistochemical expression of linker for activation of T-cells (LAT) subdivided MEITL into a LAT expressing subset (33%) and a LAT silent subset (67%) with a potentially earlier disease onset in LAT-positive MEITL.

Clinicopathologic Spectrum of Gastrointestinal T-cell Lymphoma: Reappraisal Based on T-cell Receptor Immunophenotypes

The differential diagnosis of primary gastrointestinal EBV T-cell lymphoma (GITCL) includes enteropathy-associated T-cell lymphoma (EATL), peripheral T-cell lymphoma, not otherwise specified, adult T-cell leukemia/lymphoma, and anaplastic large cell lymphoma. Type II EATL is considered to be a tumor of intraepithelial lymphocytes. However, the evaluation of intraepithelial lymphocytosis by biopsy specimens is challenging, which poses a diagnostic problem between the EATL and peripheral T-cell lymphoma, not otherwise specified. This situation requested us to establish a pragmatic diagnostic approach for the classification of GITCL. We identified 42 cases of GITCL and analyzed clinicopathologic features, especially addressing their T-cell receptor (TCR) phenotype. Nine (21%) of 42 GITCL cases were positive for TCRγ protein expression. Among these TCRγ cases, TCRβ expression or not was detected in 5 and 4, respectively, but resulted in no further clinicopathologic differences. TCRβ positivity without TCRγ expression (βγ) was seen in 9 GITCL patients (21%). Twenty-four patients (57%) were negative for TCRβ and γ expression (βγ). Compared with TCRβγ or βγ type, TCRγ cases were characterized by exclusive involvement of intestinal sites (100% vs. 11%, P<0.001; 100% vs. 58%, P=0.032, respectively), but not of stomach (0% vs. 78%, P=0.002; 0% vs. 38%, P=0.039, respectively). Notably, TCRγ positivity was an independent unfavorable prognostic factor among our GITCL patients (P<0.001). Considering our results, TCRγ GITCL, that is, intestinal γδ T-cell lymphoma, appears to constitute a distinct disease entity.

Clinicopathological analysis of 12 patients with Epstein-Barr virus-positive primary intestinal T/natural killer-cell lymphoma (EBV+ ITNKL)

AIMS

Epstein-Barr virus-positive (EBV⁺ ) intestinal T/natural killer (NK) cell lymphoma (ITNKL) is an uncommon tumour with an extremely aggressive clinical behaviour. However, the clinicopathological characteristics of this tumour, including T cell receptor (TCR) phenotype and the patient's background, remain unknown. The aim of this study was to elucidate the detailed clinicopathological profile of EBV⁺ ITNKL.

METHODS AND RESULTS

We enrolled 12 patients with EBV⁺ ITNKL without nasal involvement into the study. All patients were characterized by involvement of the small intestine with concurrent lesions of the large intestine in two patients. Seven patients (58%) had Lugano stages IIE/IV disease and eight (67%) were categorized as high-intermediate/high-risk according to the Prognostic Index for PTCL (PIT). Three patients (25%) with an age of onset of less than 50 years had chronic active EBV infection (CAEBV). Five CD56-positive patients (42%) had a poorer prognosis than those without CD56 expression (P = 0.008). NK cell-type lymphoma defined by the absence of any TCR expression or clonal TCR-γ rearrangement was found in six patients (50%). Interestingly, EBV⁺ intra-epithelial lymphocytosis was observed in one case with a background of CAEBV.

CONCLUSIONS

This study is the first to shed light on the significant heterogeneity of EBV⁺ ITNKL and its relationship with CAEBV, especially in patients younger than 50 years of age. These observations will provide a guide for diagnostic and therapeutic approaches in routine practice.

High Expression of Intestinal Homing Receptor CD103 in Adult T-Cell Leukemia/Lymphoma, Similar to 2 Other CD8+ T-Cell Lymphomas

We investigated the expression of the αEβ7 integrin (CD103)-intestinal homing receptor of T-intraepithelial lymphocytes (IELs) in 130 cases of adult T-cell leukemia/lymphoma (ATLL). We detected CD103 lymphoma cells in 55% (31/56) of mainly gastrointestinal (GI)-involved ATLL cases. Among them, lymphoma cells of 18 cases located in other involved organs had similar CD103 expression patterns. Histologically, we found (a) increased reactive IELs in non-neoplastic mucosal layers in 28% (5/18) of surgical and mucosal resection cases, (b) preserved epithelial glands, and (c) numerous small intraepithelial ATLL nests in involved lesions in 36 (69%) and 21 (40%), respectively, of the 52 examined cases. These 3 patterns were common in intestinal type II enteropathy-associated T-cell lymphoma but were rare in intestinal EBV nasal-type/like T/natural killer (NK)-cell lymphoma. We detected CD103 tumor cells in 41% (16/39) of lymph node-involved ATLL, in 31% (11/35) of skin-involved ATLL, in 68% (21/31) of type II CD4 enteropathy-associated T-cell lymphoma cases, in 36% (8/22) of primary gastric T/NK-cell lymphomas, and in 77% (7/9) of CD8 epidermotropic mycosis fungoides. CD103 ATLL prefers involving the GI tract over the skin (P<0.05). CD103 expression in GI-involved and/or total ATLL cases was significantly higher than in other 9 T/NK-cell lymphoma groups (P<0.05 or 0.01). Only ATLL cases were commonly CD103 in CD4 T/NK-cell lymphoma groups (P<0.05 or 0.01). Human T-lymphotropic virus-1-infected CD103 T-IELs and mucosal T cells may be important sources of ATLL.

Multiple lesions of gastrointestinal tract invasion by monomorphic epitheliotropic intestinal T-cell lymphoma, accompanied by duodenal and intestinal enteropathy-like lesions and microscopic lymphocytic proctocolitis: a case series

Background

In East Asia, monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL), previously known as type II enteropathy-associated T-cell lymphoma (EATL), occurs more frequently than type I EATL, and coeliac disease is rare.

Case presentation

Here we present four cases of MEITL in Japanese patients, including the endoscopic and pathological findings of their duodenal and colorectal lesions. Tumor specimens obtained from duodenal, intestinal, and colorectal biopsies in all four patients showed a diffuse intramucosal infiltration of small to/or medium-sized lymphoma cells and numerous atypical intraepithelial lymphocytes (IELs). These cells were immunohistologically positive for CD103, CD3, CD7, CD8, CD56, and T-cell intracellular antigen-1. Upper and lower gastrointestinal and antegrade double-balloon endoscopy revealed foci of edematous mucosa, with or without villous atrophy, in the non-neoplastic mucosa. Histological studies demonstrated duodenal and intestinal enteropathy-like lesions as well as microscopic (lymphocytic) proctocolitis with increased CD3- and CD8-positive and CD56-negative T-IELs in all four patients. The clinicopathological findings of the non-neoplastic lesions were similar to those characteristic of coeliac disease, suggesting that variants of coeliac disease may be present in the prodromal lesions of MEITL.

Conclusions

Our study supports the need for random gastrointestinal biopsies to determine tumor spread, the features of MEITL in the particular patients, and the presence of prodromal non-neoplastic lesions.

Genomic and immunohistochemical profiles of enteropathy-associated T-cell lymphoma in Japan

Enteropathy-associated T-cell lymphoma (EATL) is a rare primary T-cell lymphoma of the digestive tract. EATL is classified as either Type I, which is frequently associated with and thought to arise from celiac disease and is primarily observed in Northern Europe, and Type II, which occurs de novo and is distributed all over the world with predominance in Asia. The pathogenesis of EATL in Asia is unknown. We aimed to clarify the histological and genomic profiles of EATL in Japan in a homogeneous series of 20 cases. The cases were characterized by immunohistochemistry, high-resolution oligonucleotide microarray, and fluorescence in situ hybridization (FISH) at five different loci: 1q21.3 (CKS1B), 6q16.3 (HACE1), 7p22.3 (MAFK), 9q33.3 (PPP6C), and 9q34.3 (ASS1, CARD9) using formalin-fixed paraffin-embedded sections. The histological appearance of EATL ranged from medium- to large-sized cells in 13 cases (65%), small- to medium-sized cells in five cases (25%), and medium-sized in two cases (10%). The immunophenotype was CD2(+) (60%), CD3ɛ(+) (100%), CD4(+) (10%), CD7(+) (95%), CD8(+) (80%), CD56(+) (85%), TIA-1(+) (100%), Granzyme B(+) (25%), T-cell receptor (TCR)β(+) (10%), TCRγ(+) (35%), TCRγδ(+) (50%), and double negative for TCR (six cases, 30%). All cases were EBER(-). The genomic profile showed recurrent copy number gains of 1q32.3, 4p15.1, 5q34, 7q34, 8p11.23, 9q22.31, 9q33.2, 9q34.13, and 12p13.31, and losses of 7p14.1. FISH showed 15 patients (75%) with a gain of 9q34.3 with good correlation with array comparative genomic hybridization. EATL in Japan is characterized by non-monomorphic cells with a cytotoxic CD8(+) CD56(+) phenotype similar to EATL Type II. The genomic profile is comparable to EATL of Western countries, with more similarity to Type I (gain of 1q and 5q) rather than Type II (gain of 8q24, including MYC). The 9q34.3 gain was the most frequent change confirmed by FISH irrespective of the cell origin of αβ-T-cells and γδ-T-cells.

Pathology of T-cell lymphomas: diagnosis and biomarker discovery

T-cell lymphomas are a group of predominantly rare hematologic malignancies that tend to recapitulate different stages of T-cell development, in a similar way that B-cell lymphomas do. As opposed to B-cell lymphomas, the understanding of the biology and the classification of T-cell lymphomas are somewhat rudimentary, and numerous entities are still included as 'provisional categories' in the World Health Classification of hematolopoietic malignancies. A relevant and useful classification of these disorders have been difficult to accomplish because of the rarity nature of them, the relative lack of understanding of the molecular pathogenesis, and their morphological and immunophenotypical complexity. Overall, T-cell lymphomas represent only 15 % of all non-Hodgkin lymphomas. This review is focused on addressing the current status of the categories of mature T-cell leukemias and lymphomas (nodal and extranodal) using an approach that incorporates histopathology, immunophenotype, and molecular understanding of the nature of these disorders, using the same philosophy of the most recent revised WHO classification of hematopoietic malignancies.

Profile of CD103 expression in T-cell neoplasms: immunoreactivity is not restricted to enteropathy-associated T-cell lymphoma

Intestinal intraepithelial T lymphocytes express the α E subunit of integrin αEβ7, which is detected by antibodies to CD103. Accordingly, within T-cell neoplasms, CD103 reactivity has most frequently been reported in enteropathy-associated T-cell lymphomas, which are postulated to arise from intestinal intraepithelial T lymphocytes. However, prior studies of CD103 expression in T-cell neoplasms have been limited by the requirement for fresh or frozen tissue, given the historic lack of an antibody to CD103 for use in paraffin-embedded sections. Thus, a thorough assessment of CD103 expression in a broad spectrum of T-cell neoplasms as categorized by the current classification system has not yet been performed. This study uses a newly described antibody to define the profile of CD103 immunoreactivity in paraffin sections of a wide variety of T-cell neoplasms (184 cases). Overall, 22 T-cell neoplasms (12%) were CD103 positive, including 7 of 15 gastrointestinal lymphomas (3.8% of total cases; 46% of gastrointestinal cases). In intestinal cases, CD103 positivity did not correlate with morphology, presence or absence of enteropathy, or immunohistochemical profile. A history of celiac disease was not documented in any case. Frequent but inconsistent reactivity was also noted for adult T-cell leukemia/lymphoma with 4 of 10 cases (40%) positive. In the remaining T-cell neoplasms representing most entities within the current World Health Organization classification, CD103 reactivity was sporadically observed in 11 of 159 cases (6.9%). CD103 positivity is an unusual feature in T-cell neoplasms and tends to occur in gastrointestinal lymphomas and adult T-cell leukemia/lymphoma but is not a consistent characteristic of these neoplasms.

Immunohistochemistry as a valuable tool to assess CD30 expression in peripheral T-cell lymphomas: high correlation with mRNA levels

The extended use of brentuximab-vedotin was reported for CD30(+) nonanaplastic peripheral T-cell lymphomas (PTCLs) with promising efficacy. CD30 status assessment is thus a critical factor for therapeutic decision, but the reliability of immunohistochemistry (IHC) in evaluating its expression remains to be defined. This prompted us to investigate the correlation between semiquantitative CD30 protein assessment by IHC and messenger RNA (mRNA) assessment by microarrays in a cohort of 376 noncutaneous PTCLs representative of the main entities. By IHC, CD30 expression was heterogeneous across and within entities and significantly associated with large tumor cell size. In addition to 100% anaplastic large-cell lymphomas, 57% of other PTCL entities were CD30-positive at a 5% threshold. CD30 protein expression was highly correlated to mRNA levels. mRNA levels were bimodal, separating high from low CD30-expressing PTCL cases. We conclude that IHC is a valuable tool in clinical practice to assess CD30 expression in PTCLs.

Endoscopic and clinical analysis of primary T-cell lymphoma of the gastrointestinal tract according to pathological subtype

BACKGROUND AND AIM

Little is known about the clinicopathological characteristics of primary gastrointestinal T-cell lymphomas (PGITL). This study evaluated the clinical and endoscopic features of the pathological subtypes of PGITL.

METHODS

Forty-two lesions in 36 patients with PGITL were assessed, including 15 enteropathy-associated T-cell lymphomas (EATL), 13 peripheral T-cell lymphomas (PTCL), 10 NK/T-cell lymphomas (NK/TL), and four anaplastic large cell lymphomas (ALCL).

RESULTS

PTCL occurred more frequently in the stomach and duodenum and NK/TL more frequently in the small and large intestines (P = 0.009). The endoscopic features of the four subtypes were similar (P = 0.124). Fifteen of 41 lesions (36.6%) were Epstein-Barr virus (EBV) positive, with NK/TL more likely to be EBV positive than the other types (P < 0.001). First endoscopy and first computed tomography (CT) scan indicated that 65.4% and 51.4% of the lesions, respectively, were malignant, and that 43.2% and 42.3%, respectively, were GI lymphomas. The two modalities together correctly diagnosed about half of the lesions before biopsy. Intestinal perforation was associated with small bowel location (P < 0.001) and infiltrative type (P = 0.009), and was more common in NK/TL than in the other subtypes (P = 0.015). Multivariate analysis showed that higher international prognosis index (P = 0.008) and the presence of complications (P = 0.006) were associated with poor prognosis. Survival was poorer in patients with small bowel lesions than with lesions at other locations (P = 0.048).

CONCLUSIONS

The four main pathological types of PGITL differed in clinical characteristics. As PGITL was often not diagnosed by initial endoscopic or radiological examination, a high index of suspicion is necessary to ensure its early diagnosis.

Detailed clinicopathological characteristics and possible lymphomagenesis of type II intestinal enteropathy-associated T-cell lymphoma in Japan

Twenty-six Japanese cases of type II enteropathy-associated T-cell lymphoma (EATL) were examined. Multiple tumors throughout the small intestine were found in 15 patients (58%) and duodenal and colonic mucosal lesions in 8 and 6 cases, respectively. Histologically, intramucosal tumor spread and a zone of neoplastic intraepithelial lymphocytes (IELs) neighboring the main transmural tumors were detected in 20 (91%) and 17 (77%) of the 22 cases examined, respectively. Inside and outside the IEL zone, some degree of enteropathy with many reactive small IELs and villous atrophy was detected in 11 cases (50%). Immunohistologically, many CD56/CD8-positive small IELs were found in the enteropathic lesions of 4 (36%) and 7 (64%) of these 11 cases. Lymphoma cells expressed tyrosine kinase receptor c-Met, serial phosphorylated (p)-mitogen-activated protein kinase/extracellular signal-regulated kinase, c-Myc, and Bcl2 in 18 (78%), 21 (91%), 11 (42%), and 19 (73%) of the total cases, respectively. By fluorescence in situ hybridization, chromosomal loci 7q31 (c-Met) and 8q24 (c-Myc) were amplified in 11 (65%) and 12 (71%) of the 17 cases analyzed. Gain of 7q31 and c-Met expression were significantly (P < .01) higher than in peripheral CD8-positive T-cell or CD56-positive natural killer-cell lymphomas. Enteropathy was seen near the IEL zone in type II EATL, and activation of the c-Met, mitogen-activated protein kinase/extracellular signal-regulated kinase-mitogen-activated protein kinase pathway, and c-Myc-Bcl2-mediated cell survival may play important roles in lymphomagenesis, converting enteropathy to type II EATL. Seven cases in the early clinical stages I and II-1 showed significantly (P < .01) better prognoses than did those in the advanced stages. Early detection of the mucosal lesions and tumors may improve patient prognosis.

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.

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.

Intestinal γδ T-cell lymphomas are most frequently of type II enteropathy-associated T-cell type

Enteropathy-associated T-cell lymphoma includes type I cases and distinctive type II cases that, according to 2008 and 2010 World Health Organization descriptions, are T-cell receptor β+. Although T-cell receptor γδ enteropathy-associated T-cell lymphomas are reported, it is unknown if they have distinctive features and if they should be categorized as enteropathy-associated T-cell lymphoma or as a mucocutaneous γδ T-cell lymphoma. To address these questions, the clinicopathologic, immunophenotypic, molecular, and cytogenetic features of 5 γδ-enteropathy-associated T-cell lymphomas were investigated. Only 1 patient had celiac disease and had type I enteropathy-associated T-cell lymphoma, and the others fulfilled the histopathologic criteria for type II enteropathy-associated T-cell lymphoma. All lacked cutaneous involvement. A celiac disease-associated HLA type was found in the patient with CD and one of four others. All were T-cell receptor γ+, T-cell receptor δ+, βF1-, CD3+, CD7+, CD5-, CD4-, and TIA-1+ with variable staining for CD2 (3/5), CD8 (2/5), Granzyme B (1/5), and CD56 (4/5). Fluorescence in situ hybridization demonstrated 9q34 gains in 4 cases, with 9q33-34 gains by single nucleotide polymorphism in 3 of these. Single nucleotide polymorphism analysis also demonstrated gains in 5q34-q35.1/5q35.1 (4/5), 8q24 (3/5), and in 32 other regions in 3 of 5 cases. Vδ1 rearrangements were identified in 4 of 4 cases with documented clonality showing the same clone in normal-appearing distant mucosa (3/3 tested cases). Thus, γδ-enteropathy-associated T-cell lymphomas share many features with other enteropathy-associated T-cell lymphoma and are mostly of type II. Their usual nonactivated cytotoxic phenotype and Vδ1 usage are features unlike many other mucocutaneous γδ T-cell lymphomas but shared with hepatosplenic T-cell lymphoma. These findings support the conclusion that a γδ T-cell origin at extracutaneous sites does not define a specific entity.

Paediatric T-cell lymphoma of the appendix: a case report

A 7-year-old boy with no history of malnutrition or diarrhoea complained of acute abdominal pain, was diagnosed with acute appendicitis, and underwent appendectomy. Histologically, a diffuse infiltrate of large atypical lymphoid cells was found in the entire appendiceal wall. Immunohistochemical examination revealed that the tumour cells expressed T-cell receptor (TCR)-βF1, CD3, CD4, CD25, cytotoxic-related protein TIA1 and granzyme-B, but were negative for CD8, Foxp3, CD20, CD30 and CD56. Polymerase chain reaction (PCR) revealed clonal bands of TCR-γ gene products in the tumour tissue. No anti-cytomegalovirus antibody-positive cells were detected. In situ hybridization revealed no nuclear signals of Epstein-Barr virus (EBV)-encoded RNA. Helicobacter pylori infection was detected in tumour tissue by anti-East Asian cytotoxin-associated gene (Cag) A antibody and PCR using its specific primers. The patient received chemotherapy and has remained in remission for 2 years. To the best of our knowledge, only two cases of appendiceal T-cell non-Hodgkin lymphoma (NHL) have been reported, both in elderly patients. We believe that this is the first reported case of childhood CD4- and TIA1-positive cytotoxic T (Th1)-cell NHL in the appendix or gastrointestinal tract. Helicobacter pylori infection might be an initiator of atypical cytotoxic T-cell proliferation.

VIRTUAL SLIDES

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1302380563830412.

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).

Enteropathy-associated T-cell lymphoma (type II): a Brazilian case report

Enteropathy-associated T-cell Lymphoma (EATL) is a rare form of aggressive T-cell lymphoma. It is more prevalent in men over 60 years and the prognosis is very poor. EATL is classified into two groups based on morphology, immunohistochemistry, and genetic profile. EATL type I is highly associated with celiac disease and is more common in Western countries. EATL type II predominates over type I in Asia, where celiac disease is uncommon. We report a case of a 78-year-old previously healthy white male who presented with a 2-month history of diarrhea, weight loss and edema. The abdomen was distended and painful, and a tumor mass was palpable in the hypogastrium. Laboratory tests showed hypoalbuminemia. Serological tests for HIV, viral hepatitis and HTLV-1 were negative. The chest radiography showed pneumoperitoneum, and an exploratory laparotomy revealed perforation of the small bowel. An advanced stage (Ann Arbor IV B/Lugano IIE2B) EATL type II was diagnosed. Four cycles of chemotherapy were interspersed with several complications (anthracycline-induced cardiotoxicity, chemotherapy-induced neutropenic fever and severe sepsis). Performance status progressively worsened and he died 6 months after the diagnosis. This is an illustrative report of a rare and aggressive primary intestinal lymphoma. To the best of our knowledge, this is the first report of EATL type II in Brazil.

Genetic alterations in systemic nodal and extranodal non-cutaneous lymphomas derived from mature T cells and natural killer cells

Mature (peripheral) T-cell and natural killer (NK)-cell lymphomas comprise a series of rather different neoplasms. Based on morphologic, immunophenotypic, genetic, and clinical data, the World Health Organization classification recognizes more than 20 entities or provisional entities. The variable clinical presentations, the objective recognition and pathological stratification, the difficulties regarding treatment, and the hardly predictable response to therapy indicate that the management of these entities requires novel tools. In contrast to B-cell lymphomas or precursor T-cell neoplasms, few recurrent translocations have been identified so far in T-cell non-Hodgkin's and NK-cell lymphomas. Additionally, some of the entities recognized by the World Health Organization classification are very rare and very scarce molecular data are available for T-cell lymphomas. Here, we have reviewed published reports focusing on the genetic lesions and gene expression profiling underlying systemic nodal and extranodal non-cutaneous mature T-cell and NK-cell lymphomas. We also provide a summary of new agents in clinical development and outline some future directions.

An unusual enteropathy-associated T-cell lymphoma with MYC translocation arising in a Japanese patient: A case report

Enteropathy-associated T-cell lymphoma (EATL) is a rare peripheral T-cell lymphoma classified into 2 types, with or without celiac disease, based on histology. Type 2 EATL is less commonly associated with celiac disease, in which cells are characterized by being monomorphic and small- to medium-sized. Cells are characterized by CD8 and CD56 expression and c-MYC oncogene locus gain. We present an atypical case of type 2 EATL in the jejunum, with human T-lymphotropic virus-1 that was CD4- CD8+ CD56- CD30- CD25- TIA-1+ and granzyme B+ on immunohistological staining. It also displayed translocation of chromosome 8p24 (c-MYC), as determined by fluorescent in situ hybridization. Mucosal spreading and intraepithelial invasion by lymphoma with villous atrophy were detected adjacent to the mucosal layer. The lymphoma may be derived from intraepithelial CD8+ T cells, similar to celiac disease.

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.

Brentuximab vedotin in systemic T-cell lymphoma

INTRODUCTION

Brentuximab vedotin is an antibody-drug conjugate which consists of the anti-CD30 monoclonal antibody cAC10 conjugated with the cytotoxic agent monomethyl auristatin E (MMAE). Brentuximab vedotin has been approved by the US Food and Drug Administration for the treatment of relapsed or refractory Hodgkin's lymphoma (HL) and anaplastic large cell lymphoma (ALCL). The efficacy of brentuximab vedotin in other CD30(+) lymphomas is currently being investigated.

AREAS COVERED

In this paper, we review the currently available treatment options for systemic peripheral T-cell lymphomas (PTCL) and the role of brentuximab vedotin in relapsed or refractory ALCL. In addition, ongoing clinical trial of brentuximab vedotin in relapsed PTCL and combination therapy with other chemotherapies for initial treatment of CD30 lymphoma will also be reviewed.

EXPERT OPINION

Brentuximab vedotin has established its role in the treatment of relapsed or refractory HL and ALCL. In the next few years, the efficacy of this agent in other CD30(+) lymphomas will be described. The safety and efficacy of several brentuximab-based combination regimens, including use as frontline chemotherapy is under investigation.

Lymphoproliferative disorders of the gastrointestinal tract: a review and pragmatic guide to diagnosis

CONTEXT

The gastrointestinal tract is the most common site of extranodal lymphomas. Although all histologic categories of malignant lymphoma develop in the gastrointestinal tract, large B-cell lymphomas predominate, followed by extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT) type; the latter is especially prevalent in stomach. The acceptance of extranodal marginal zone lymphoma of MALT type as a clinicopathologic entity has reduced the number of cases that formerly were interpreted as florid lymphoid hyperplasia ("pseudolymphoma"). Nonetheless, the distinction of lymphoid hyperplasia from a lymphoma of MALT type in small biopsy specimens remains problematic.

OBJECTIVE

To assess the relevant morphologic, immunologic, molecular, and genetic properties of gastrointestinal lymphomas and to present a feasible tactic for diagnosis, expressly for small biopsy specimens.

DATA SOURCES

Case-derived material and literature review using PubMed (National Library of Medicine).

CONCLUSIONS

Most gastrointestinal lymphomas are readily amenable to an unqualified diagnosis, primarily those cases consisting of monomorphic large cells whether of B- or T-cell lineage, including cases associated with enteropathy. Diagnosis for infiltrates dominated by small lymphocytes remains taxing, as the differential diagnosis embraces not only MALT lymphoma and lymphoid hyperplasia but also mantle cell lymphoma, follicular lymphoma, and chronic lymphocytic leukemia/small lymphocytic lymphoma. Adherence to strict morphologic criteria is the standard for diagnosis, but these criteria should be augmented by immunologic studies together with judicious use of molecular techniques to determine clonality. In establishing a diagnosis of gastric marginal zone lymphoma of MALT type, determination of t(11;18)(q21;q21) status may be required since this translocation has clinical ramifications.

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."