Enteropathy-associated T-cell lymphoma

1.1. Definition 

Enteropathy-associated T-cell lymphoma (EATL) is an intestinal tumour of intraepithelial T lymphocytes, usually presenting as a neoplasm composed of large lymphoid cells and often associated with necrosis and an inflammatory background, including large numbers of histiocytes and eosinophils. The adjacent small intestinal mucosa shows villous atrophy, crypt hyperplasia, increased lamina propria lymphocytes and plasma cells, and intraepithelial lymphocytosis. In 10–20% of cases, the lymphoma is composed of monomorphic medium-sized cells with no inflammatory background and rare necrosis (type II EATL). Intestinal intraepithelial α–β T-cells, in various stages of transformation, have been postulated as the normal-cell counterpart for EATL. This seems to be supported by immunophenotypic and genotypic data, as well as by the cytotoxic differentiation observed in the neoplastic cells of almost all cases of EATL [1].

1.2. Incidence and risk factors 

EATL represents 10–25% of all primary lymphomas of the small bowel, and is the most common neoplastic complication of coeliac disease. EATL is uncommon in most parts of the world, but is seen with greater frequency in those areas with a high prevalence of coeliac disease, in particular Northern Europe. Two to three percent of patients affected by coeliac disease will develop an intestinal lymphoma, and 65% of them will have T-immunophenotype [2]. A prospective cohort study of incident malignancy rates in patients with coeliac disease showed a standardized incidence ratio of 5.81 (1.58–14.86) for all non-Hodgkin's lymphomas and 40.51 (1.03–225.68) for small bowel lymphomas during 5684 person years of follow-up in southern Derbyshire [3]. The interval between diagnosis of coeliac disease and development of lymphoma is extremely variable, oscillating from 2 months to more than 5 years [4]. Human leukocyte antigen (HLA) genotyping shows that patients with EATL have the coeliac disease-associated DQA1*0501, DBQ1*0201 phenotype, and additional HLA-DR/DQ alleles may increase the risk of lymphoma [5]. In some cases of refractory coeliac disease (RCD), the intraepithelial lymphocytes (IEL) are phenotypically aberrant showing down-regulation of CD8 similar to the IEL in mucosa adjacent to EATL. These cases also show monoclonal T-cell rearrangement of the IEL similar to the clonal rearrangements that may be found in the enteropathic mucosa adjacent to EATL [6], suggesting that the immunophenotypically aberrant IEL constitute a neoplastic population. In those patients with RCD who subsequently develop EATL, the IEL share the same monoclonal TCRγ as the subsequent T-cell lymphoma [7], [8], [9], [10]. Furthermore, the IEL in cases of RCD carry gains of chromosome 1q in common with EATL [11]. Thus, RCD in which the IEL show these immunophenotypic and genetic features can be considered as examples of intraepithelial T-cell lymphoma or, alternatively, EATL in situ. The monomorphic form of EATL may also be preceded by RCD in which the immunophenotype of the IEL is similar to that of the neoplastic cells in the subsequent lymphoma, namely CD8+ and CD56+. This variant occurs sporadically, without risk factors for coeliac disease, and appears to have a broader geographic distribution. In patients without a prior diagnosis of coeliac disease, EATL is a very rare disorder, and the diagnosis in such cases is often difficult and delayed. Another condition associated with EATL is ulcerative jejunitis. Small bowel is the most frequent extranodal site of presentation among NHLs developing in solid-organ graft recipients who did not receive cyclosporine [12], especially renal graft recipients. In these patients, in contrast to cases that occur in individuals treated with cyclosporine, the time interval between grafting and lymphoma development is longer than 12 months [13].

2.1. Morphology 

EATL more often occurs in the jejunum or ileum in the form of one or more ulcerating mucosal lesions that invade the wall of the intestine and frequently cause perforation. This is in contrast to what seen in B-cell lymphomas that tend to affect the distal or terminal ileum by producing annular infiltration or polypoid masses [14], [15]. Classical EATL shows a wide range of cytological appearances [16], [17]. Most commonly, neoplastic cells are rather monotonous, medium-large sized with round or indented nuclei, prominent nucleoli and an evident rim of pale staining cytoplasm. Less frequently, they are pleomorphic, mimicking anaplastic large cell lymphoma. An inflammatory background is usually present: it consists of histiocytes and eosinophils that at times are so numerous as to obscure the lymphomatous population. Infiltration of the epithelium of individual crypts is recorded in many cases. The intestinal mucosa adjacent to the neoplasm frequently shows enteropathy with villous atrophy, crypt hyperplasia, increased lamina propria lymphocytes and plasma cells and intraepithelial lymphocytosis [18]. In type II EATL, the neoplastic cells are homogeneously medium-sized with darkly stained nuclei and a moderate rim of pale cytoplasm. The adjacent mucosa does also show villous atrophy and crypt hyperplasia with striking intraepithelial lymphocytosis. However, there is no inflammatory background and necrosis is less evident than in classical EATL.

2.2. Immunophenotype 

In EATL, the tumour cells are CD3+, CD5−, CD7+, CD8−/+, CD4−, CD103+, TCRβ+/−, and contain cytotoxic molecules (TIA-1, granzyme a, granzyme M and perforin). In almost all cases, a varying proportion of tumour cells express CD30. The intraepithelial lymphocytes in the adjacent enteropathic mucosa may show the same phenotype as lymphomatous elements. Type II EATL has a distinctive immunophenotype. The tumour cells are CD3+, CD4−, CD8+, CD56+ and TCRβ+.

2.3. Genetic features 

TCRβ and γ genes are clonally rearranged in all morphological variants. Patients with EATL usually carry the HLADQA1*0501, DQB1*0201 genotype that is seen in more 90% of patients with coeliac disease [19]. About 70% of EATL cases harbour complex segmental amplifications of the 9q31.3-qter chromosome region or, alternatively, show del16q12.1, which is prevalent in both morphological variants of EATL. Chromosomes gains in 1q and 5q are frequent in classical EATL, while 8q24 (myc) amplifications are more common in the monomorphic variant [20], [21], [22].

3.1. Clinical presentations 

Usually, EATL occurs in adults, often with a history of gluten-sensitive enteropathy, but occasionally as the initial event in a patient found to have the typical histological features of sprue in the resected intestine. Less commonly, it arises in patients without evidence of enteropathy; in these cases, diagnosis is difficult and delayed due to the non-specific nature of the symptoms and a very low index of clinical suspicion. Patients generally present with abdominal pain, often associated with jejunal perforation, weight loss, diarrhoea, or bowel obstruction. Since obstruction and perforation are common, many cases are diagnosed at laparotomy. EATL is characterized by multifocal presentation in 10–25% of cases [23]. Small-bowel lymphoma is more common than large-bowel or rectal lymphomas. The higher frequency of intestinal perforation at diagnosis may account for the high perioperative complication rate in this lymphoma. A relationship between EATL and eosinophilia has been seldom reported [24]. Neurologic symptoms are reported in approximately 6% of adults with celiac disease; cerebellar ataxia is the most frequent symptom reported. Generally, any extra-intestinal manifestation of a T-cell NHL in a patient with celiac disease should be considered as a possible manifestation of a cryptogenic EATL, even if the enteropathy is clinically asymptomatic [25].

4.1. Staging procedures 

Complete staging work-up for EATL includes an accurate physical examination (Waldeyer's ring involvement should be excluded), complete haematological and biochemical exams, total-body computerized tomography, gastrointestinal tract examination, and bone marrow aspirate and biopsy. Unlike primary gastric lymphoma, where a surgical approach is progressively being replaced by conservative management, most patients with EATL still undergo exploratory laparotomy for diagnosis and staging. In patients with histopathological diagnosis of EATL, extensive staging should be limited to selected cases (i.e., RCD) considering that systemic chemotherapy is indicated in all patients independently of stage and that several procedures may result in chemotherapy delay. In patients with EATL who have not had a surgical exploration, barium studies of the small and large intestine and pancolonscopy with biopsy sampling of all macroscopically evident lesions should be performed because of the frequent multifocal nature of this malignancy. Abdominal staging, with evaluation of potential hepatic or splenic involvement in EATL is usually performed during exploratory laparotomy. In patients managed with a conservative approach, abdominal staging should follow the general principles as for all NHL. 18F-FDG PET is able to discriminate between refractory celiac disease and EATL; in 38 examined patients, PET revealed sites affected by EATL as confirmed on biopsy in all patients, whereas CT scan was false negative in one patient. False-positive results in PET may be due to inflammation in refractory celiac disease [26].

4.2. Staging system 

The Ann Arbor staging system [27], currently used for the majority of non-Hodgkin's lymphomas, has been considered unsatisfactory for EATL. Several alternative staging systems have been used for this malignancy [28], [29], [30]. An International Workshop of 1994 recommended the following classification [30]:

Patients should be divided in two subsets according to the presence (A) or absence (B) of systemic symptoms. Fever of no evident cause, night sweats and weight loss of more than 10% of body weight are considered systemic symptoms. These symptoms must be meticulously evaluated because they are frequently due to causes other than intestinal lymphoma. Several EATL patients have remarkable weight loss due to severe associated enteropathy; fever can be secondary to a concomitant but not obvious sepsis in an immunocompromised individual. The presence of bulky mass, such as a lesion of 10cm or more in the longest diameter, is designated as “X”.

5.1. Natural history 

EATL is an aggressive malignancy which, if untreated, leads invariably to death due to multifocal intestinal perforation caused by refractory malignant ulcers. Since its association with gluten-sensitive enteropathy, most patients with EATL are extremely compromised from an immunological and nutritional point of view. Most patients with EATL are managed with a surgical approach as the primary strategy. Even if surgical operation is not a curative treatment, debulking and resection of masses with high-risk of perforation or occlusion are frequently indicated in these patients. The higher frequency of intestinal perforation at diagnosis may account for the high perioperative complication rate in this lymphoma. The prognosis of EATL is very poor compared with B-cell intestinal lymphomas [14]. Usually, EATL shows low chemosensitivity, rapid tumour growth and a tendency to dissemination, with ∼80% of responsive patients experiencing relapse, even after 5 years of follow-up. Moreover, the higher incidence of severe postsurgical complications and the poor nutritional and immunological conditions of these patients lead to progressive clinical deterioration, preventing the use of adequate and opportune treatment. Overall, the dismal prognosis for EATL patients, in part, reflects late diagnosis and poor performance status at the time of presentation [31].

5.2. Prognostic factors 

Considering the heterogeneity and the small number of patients reported in any single series, reliable prognostic factors for EATL have not been established. In effect, the majority of EATL patients have been reported as part of large series of patients with different primary gastrointestinal lymphomas. These series were usually managed heterogeneously and included patients with all stages of disease. Stage is the main prognostic factor in EATL, with a 5-year cause-specific survival higher than 60% for patients with limited disease and 25% for those with advanced EATL [32], [33]. In the largest series of gastrointestinal lymphoma, bulky lesion, stage, histology, immunophenotype, B symptoms, and LDH ratio have been reported as the main prognostic indicators [32], [33], [34], [35]. In a large series of intestinal lymphomas, perforation, high-grade histology, multiple tumours and advanced stage have been identified as the main adverse prognostic features [14].

6.1. First-line treatment 

A standard treatment for patients with EATL has not been established, and overall reported results with varied modalities are unsatisfactory. The role of surgery is limited to debulking or resection of masses with high-risk of obstruction or perforation and is suitable for individual clinical use on a type R basis. Radiation therapy has been indicated in some patients presenting with bulky disease, rectal lymphoma or incomplete resection. Involved-field delivering 35Gy in 1.5–2-Gy daily fractions, five fractions a week is suitable for individual clinical use on a type R basis [36]. Combined treatment with primary debulking resection and systemic conventional-dose anthracycline-containing chemotherapy, which may or may not be followed by radiation therapy, is suitable for individual clinical use on a type 3 level of evidence, with an ORR of 58%, a 5-year FFS of 3% and a 5-year OS of 20–25% [14], [31], [33], [35], [37]. Relapses after CHOP or CHOP-like chemotherapy occur 1–60 months from diagnosis in ∼80% of responsive patients, with a mortality of 85% due to progressive disease or complications [31]. Unfortunately, a considerable proportion of EATL patients are unable to complete chemotherapy and do not receive radiotherapy due to rapid progression of disease during primary treatment, poor nutritional status, performance status impairment and local and systemic complications [38]. Many patients require enteral or parenteral feeding to improve chemotherapy tolerability [31]. Anecdotal data from retrospective small series suggest a better prognosis in patients who have undergone macroscopically complete resection compared with those who have residual disease [39], [40], [41], and the use of chemotherapy in cases of incomplete resection is associated with a 5–15% incidence of intestinal perforation and other complications.

Given the minimal utility of standard anti-lymphoma chemotherapy combinations in patients with EATL, some authorities have assessed feasibility and activity of high-dose chemotherapy supported by autologous stem cells transplantation (ASCT) as upfront therapeutic option both in small series [42], [43], [44] and retrospective studies [45], [46], [47]. A small study reported promising results using two cycles of IVE (ifosphamide, etoposide, epirubucin) followed by two cycles of high-dose methotrexate (3g/mq) and BEAM conditioning (carmustine, etoposide, cytarabine, melphalan) supported by ASCT; four patients remained alive and disease-free after 2–4 years from treatment, while two patients experienced relapse [45]. A Nordic Lymphoma phase II study on 160 patients with different T-cell lymphoma categories treated with six courses of CHOEP-14 (cyclophosphamide, doxorubicin, etoposide, vincristine, and prednisone administered every 2 weeks) followed by ASCT showed a 3-year OS and PFS of 52% and 47% (intention-to-treat) in the subgroup of 21 patients with EATL [46]. A recently reported series of 26 patients with EATL treated with a IVE/MTX combination (ifosfamide, vincristine, etoposide/methotrexate) supported by ASCT showed a 5-year PFS and OS of 52% and 60%, respectively, which was significantly improved compared with the historical group treated with anthracycline-based chemotherapy (22% and 22%, respectively) [47]. Even if only half of patients actually received conditioning and ASCT and that one third of patients died of lymphoma or complications, this study, and the previous ones, clearly supports the idea that patients tolerating more intensive approaches may benefit. Interestingly, chemotherapy supported by ASCT may also prevent EATL development in patients with RCD [48]. In a retrospective series of 13 patients with RCD type II, seven patients successfully underwent conditioning with fludarabine and melphalan supported by ASCT, with a significant reduction in the aberrant T-cells in duodenal biopsies associated with improvement in clinical well-being and normalization of hematologic and biochemical markers [49].

Alemtuzumab, a humanized anti-CD52 monoclonal antibody currently used in the treatment of chronic lymphocytic leukemia, has been used in different chemoimmunotherapy combinations in the treatment of T-cell lymphomas [50], [51], [52], but only rarely in EATL. An elderly patient with poor PS and extra-intestinal dissemination of EATL has been successfully treated at the time of diagnosis and at relapse with a combination of alemtuzumab and gemcitabine [53]. A patient with EATL has been treated with alemtuzumab-CHOP combination at diagnosis in a prospective phase II trial on T-cell lymphomas achieving a short-lived complete remission [51]. Interestingly, this monoclonal antibody has been successfully used in a patient affected by RCD and increased risk for EATL [54]. Alemtuzumab may therefore represent a new tool for improving the outcome of EATL patients and deserves to be assessed in future trials on this aggressive lymphoma.

6.2. Treatment of relapsed or refractory disease 

A standard therapeutic option for patients with relapsed or refractory disease has not been established. High-dose chemotherapy supported by ASCT should be taken into account in these patients considering the aggressive behaviour of relapsed T-cell lymphomas and the lack of valid therapeutic alternatives. The rationale for using this strategy is immunoablation using high-dose chemotherapy, with subsequent regeneration of naïve T-lymphocytes derived from reinfused haematopoietic progenitor cells. Moreover, the use of ASCT allows the administration of high-dose chemotherapy resulting in a prompt remission in these therapy-refractory patients [55]. However, the worldwide experience is very limited, and this remains an investigational option [56]. Special attention should be paid to eligibility criteria for intensive therapeutic strategies, considering the poor performance status of these patients at relapse. In some cases, whole-abdomen irradiation with 20–25Gy delivered in 1- to 1.25-Gy daily fractions may be indicated for palliative treatment [57]. Alemtuzumab in combination with DHAP regimen has been used as salvage therapy for extranodal T/NK lymphomas and other T-cell lymphomas with promising results [58]. This strategy deserves to be assessed in EATL to improve disease control and survival.