Indolent T-cell lymphoproliferative disease with synchronous diffuse large B-cell lymphoma: A case report

Indolent T-Cell/Natural Killer-Cell Lymphomas/Lymphoproliferative Disorders of the Gastrointestinal Tract-What Have We Learned in the Last Decade?

Primary gastrointestinal (GI) T-cell and natural killer (NK)-cell lymphomas/lymphoproliferative disorders (LPD) are uncommon, and they are usually aggressive in nature. However, T-cell and NK-cell lymphoma/LPD of the GI tract with indolent clinical course has been reported over the past 2 decades. Indolent T-cell LPD was formally proposed a decade ago in 2013 and 4 years later recognized as a provisional entity by the revised fourth edition of WHO Classification of Tumours of Haematopoietic and Lymphoid Tissues in 2017. Indolent T-cell LPD of the GI tract has been changed to indolent T-cell lymphoma of the GI tract as a distinct entity by the fifth edition of WHO Classification of Haematolymphoid Tumours, but the International Consensus Classification of mature lymphoid neoplasms prefers indolent clonal T-cell LPD of the GI tract instead. In the past decade, indolent lymphoma/LPD of the GI tract has been expanded to NK cells, and as such, indolent NK-cell LPD of the GI tract was recognized as an entity by both the fifth edition of WHO Classification of Haematolymphoid Tumours and the International Consensus Classification. The underlying genetic/molecular mechanisms of both indolent T-cell lymphoma/LPD of the GI tract and indolent NK-cell LPD of the GI tract have been recently discovered. In this review, we describe the history; salient clinical, cytohistomorphologic, and immunohistochemical features; and genetic/genomic landscape of both entities. In addition, we also summarize the mimics and differential diagnosis. Finally, we propose future directions with regard to the pathogenesis and clinical management.

Indolent T-cell lymphoproliferative disorder of gastrointestinal tract with unusual clinical courses: report of 6 cases and literature review

Indolent T-cell lymphoproliferative disorder of the gastrointestinal tract (iTLPD-GI) is a rare neoplasm usually having an indolent clinical course and easily misdiagnosed as inflammatory bowel disease or other T-cell lymphomas. A subset of the disorders that progressed to overt peripheral T-cell lymphoma have been reported, and the etiology and pathogenesis are poorly understood. The current study retrospectively examined the pathological, molecular, and clinical features of 6 cases of iTLPD-GI. Hematoxylin and eosin staining, immunohistochemistry, in situ hybridization, T-cell receptor gene rearrangement, and next-generation sequencing (NGS) were performed with the diseased tissues. All the 6 patients were immunocompetent Chinese men, who presented with recurrent abdominal pain and diarrhea for 4 to 13 years. Histologically, the intestinal tissue was expanded by lymphoid infiltration, composed of small-to-medium-sized lymphocytes with gland intact. The neoplastic cells were CD4 - /CD8 + with expression of TIA1 and variable granzyme B in five cases, and the other one was CD4 + /CD8 - . Two of the 5 patients progressed to more aggressive T-cell lymphoma and died of disease with complications. NGS identified TET2 and DDX3X mutations in patient 1, and BIRC6 and REV3L mutations in patient 2. Literature review indicated that iTLPD-GI with CD4 - /CD8 + immunophenotype was more commonly reported in Chinese cases. Our limited data indicated CD4-/CD8 + iTLPD-GI have similar potential to progress to more aggressive T-cell lymphoma as that of CD4 + /CD8 - , and gradually increased expression of granzyme B and Ki-67 may be early signs of the disease progression. Gain of novel gene mutations may be indicators of the pathogenesis.

CD8-positive indolent T-Cell lymphoproliferative disorder of the gastrointestinal tract: A case report and review of literature

BACKGROUND

Indolent T-cell lymphoproliferative disorder of the gastrointestinal tract (ITLPD-GI), a primary tumor forming in the gastrointestinal (GI) tract, represents a rarely diagnosed clonal T-cell disease with a protracted clinical course.

CASE SUMMARY

This report presented a 45-year-old male patient with a 6-year history of anal fistula and a more than 10-year history of recurrent diarrhea who was not correctly diagnosed until the occurrence of complications such as intestinal perforation. Postsurgical histopathological analysis, combined with hematoxylin-eosin staining, immunohistochemistry and TCRβ/γ clonal gene rearrangement test, confirmed the diagnosis of CD8+ ITLPD-GI.

CONCLUSION

Individuals with this scarce lymphoma frequently show non-specific symptoms that are hard to recognize. So far, indolent CD8+ ITLPD-GI has not been comprehensively examined. The current mini-review focused on evaluating indolent CD8+ ITLPD-GI cases based on existing literature and discussing future directions for improved differential diagnosis, detection of genetic and epigenetic alterations, and therapeutic target identification.

Primary Gastrointestinal T-Cell Lymphoma and Indolent Lymphoproliferative Disorders: Practical Diagnostic and Treatment Approaches

Simple Summary

It is challenging for pathologists to diagnose primary gastrointestinal T-cell neoplasms. Besides the rarity of the diseases, the small biopsy material makes it more difficult to differentiate between non-neoplastic inflammation and secondary involvement of extra gastrointestinal lymphoma. Since this group of diseases ranges from aggressive ones with a very poor prognosis to indolent ones that require caution to avoid overtreatment, the impact of the diagnosis on the patient is enormous. Although early treatment of aggressive lymphoma is essential, the treatment strategy is not well established, which is a problem for clinicians. This review provides a cross-sectional comparison of histological findings. Unlike previous reviews, we summarized up-to-date clinically relevant information including the treatment strategies as well as practical differential diagnosis based on thorough literature review.

Abstract

Primary gastrointestinal (GI) T-cell neoplasms are extremely rare heterogeneous disease entities with distinct clinicopathologic features. Given the different prognoses of various disease subtypes, clinicians and pathologists must be aware of the key characteristics of these neoplasms, despite their rarity. The two most common aggressive primary GI T-cell lymphomas are enteropathy-associated T-cell lymphoma and monomorphic epitheliotropic intestinal T-cell lymphoma. In addition, extranodal natural killer (NK)/T-cell lymphoma of the nasal type and anaplastic large cell lymphoma may also occur in the GI tract or involve it secondarily. In the revised 4th World Health Organization classification, indolent T-cell lymphoproliferative disorder of the GI tract has been incorporated as a provisional entity. In this review, we summarize up-to-date clinicopathological features of these disease entities, including the molecular characteristics of primary GI T-cell lymphomas and indolent lymphoproliferative disorders. We focus on the latest treatment approaches, which have not been summarized in existing reviews. Further, we provide a comprehensive review of available literature to address the following questions: How can pathologists discriminate subtypes with different clinical prognoses? How can primary GI neoplasms be distinguished from secondary involvement? How can these neoplasms be distinguished from non-specific inflammatory changes at an early stage?

Indolent T-Cell Lymphoproliferative Disorders of the Gastrointestinal Tract (iTLPD-GI): A Review

Simple Summary

This review aims to better define the clinical, pathological, and molecular features of the novel lymphoproliferative disease termed “indolent T-cell lymphoproliferative disorder of the gastro-intestinal tract (iTLPD-GI)”, to discuss potential pitfalls in differentiating this entity from other neoplastic and non-neoplastic disorders arising at the same site, and to point out a biomarker-based approach to the diagnosis.

Abstract

iTLPD-GI is a low-grade clonal T-cell lymphoproliferative disease arising in GI organs. It is an uncommon disease, and only recently has it been enlisted as a distinct provisional entity in the current WHO Classification. Data from the literature disclose high heterogeneity in terms of pathological and molecular features; on the other hand, establishing an accurate diagnosis of iTLPD-GI is of pivotal importance, since treatment options are different from that of other, more frequent lymphomas that arise in the gastrointestinal tract. In this review, we aimed to better define this novel entity, and to identify useful diagnostic biomarkers; moreover, we provide a biomarker-based approach to the diagnosis and describe the most common issues in differentiating iTLPD-GI from other neoplastic and non-neoplastic disorders.

Indolent T cell lymphoproliferative disorder of the gastrointestinal tract: an uncommon case with lymph node involvement and the classic Hodgkin's lymphoma

Here we describe an unusual case of an indolent CD8+ T-cell lymphoproliferative disorder in the gastrointestinal tract (ITCLD-GT) accompanied by neck lymph node infiltration and new onset of classic Hodgkin's lymphoma after two years follow-up. Previously, this 42-year-old Asian man suffered from diarrhea and abdominal pain for two years. Intestinal biopsies showed a group of small to intermediate-sized lymphocytes which were monomorphic as well as arranged in a nodular pattern with no clear boundary and were diagnosed as ITCLD-GT. He did not receive chemotherapy or have any disease progression in the gastrointestinal tract (GIT) during the follow-up until a development of neck lymphadenopathy, which led to an eventual mixed cellularity type of Hodgkin's lymphoma, one type of classic HL diagnosis. Interestingly, besides the Hodgkin's cells, the same pathological T-cells in the GIT were present in the Hodgkin's lymphoma lesions. These two pathological T cells in GIT and neck lymph node had the identical histopathological and molecular abnormalities that confirmed the abenteric distant infiltration of ITCLD-GT to the neck lymph node in this patient. This is the first case of ITCLD-GT that has a definite distant lymph node invasion. ITCLD-GT usually has a relatively good prognosis but patients with ITCLD-GT may have abenteric distant infiltration. Thus, long-term follow-up and further study of the underlying mechanisms of this process are necessary.

Indolent T-Cell Lymphoproliferative Disease of the GI Tract: Insights for Better Diagnosis, Prognosis, and Appropriate Therapy

Indolent T-cell lymphoproliferative disease of the gastrointestinal tract (indolent GI T-LPD) is a benign neoplasm of CD4⁺ or CD8⁺ T cells that form primary tumors in the GI tract. Indolent GI T-LPD has recently been provisionally recognized as a distinct entity by the 2016 revision of the WHO classification of lymphoid neoplasms. Appropriate diagnosis of these cases is challenging as they may be misdiagnosed as T cell lymphoma that has an aggressive clinical course. Consequently, aggressive therapeutic approaches were usually chosen to treat these cases with no obvious benefit for most of the patients and potential side effects. Moreover, inflammatory diseases of the GI tract with similar symptoms may lead to misdiagnosis that leads to delays in administration of proper therapeutics against these cases. Therefore, it is of utmost importance to identify prognostic genetic biomarkers at the time of diagnosis for optimal medical care of these patients. TCR clonality analyses may not be useful for distinguishing these benign neoplasms from aggressive gastrointestinal T cell lymphomas; however, molecular genetic tests may prove useful as recurrent STAT3-JAK2 fusions, which may have diagnostic, prognostic or therapeutic value, have recently been identified. However, there is still lack of comprehensive information on the genetic and epigenetic factors associated with pathogenesis of indolent GI T-LPD. In this mini-review, we focus on the so far reported literature on indolent GI T-LPD cases, and discuss future directions for better differential diagnosis, risk stratification, and therapeutic target discovery with a special focus on the genetic and epigenetic alterations.

Indolent T cell lymphoproliferative disorder of the gastrointestinal tract: an uncommon case with lymph node involvement and the classic Hodgkin's lymphoma

Here we describe an unusual case of an indolent CD8+ T-cell lymphoproliferative disorder in the gastrointestinal tract (ITCLD-GT) accompanied by neck lymph node infiltration and new onset of classic Hodgkin's lymphoma after two years follow-up. Previously, this 42-year-old Asian man suffered from diarrhea and abdominal pain for two years. Intestinal biopsies showed a group of small to intermediate-sized lymphocytes which were monomorphic as well as arranged in a nodular pattern with no clear boundary and were diagnosed as ITCLD-GT. He did not receive chemotherapy or have any disease progression in the gastrointestinal tract (GIT) during the follow-up until a development of neck lymphadenopathy, which led to an eventual mixed cellularity type of Hodgkin's lymphoma, one type of classic HL diagnosis. Interestingly, besides the Hodgkin's cells, the same pathological T-cells in the GIT were present in the Hodgkin's lymphoma lesions. These two pathological T cells in GIT and neck lymph node had the identical histopathological and molecular abnormalities that confirmed the abenteric distant infiltration of ITCLD-GT to the neck lymph node in this patient. This is the first case of ITCLD-GT that has a definite distant lymph node invasion. ITCLD-GT usually has a relatively good prognosis but patients with ITCLD-GT may have abenteric distant infiltration. Thus, long-term follow-up and further study of the underlying mechanisms of this process are necessary.

Genetic and phenotypic characterization of indolent T-cell lymphoproliferative disorders of the gastrointestinal tract

Indolent T-cell lymphoproliferative disorders of the gastrointestinal tract are rare clonal T-cell diseases that more commonly occur in the intestines and have a protracted clinical course. Different immunophenotypic subsets have been described, but the molecular pathogenesis and cell of origin of these lymphocytic proliferations is poorly understood. Hence, we performed targeted next-generation sequencing and comprehensive immunophenotypic analysis of ten indolent T-cell lymphoproliferative disorders of the gastrointestinal tract, which comprised CD4⁺ (n=4), CD8⁺ (n=4), CD4⁺/CD8⁺ (n=1) and CD4^-/CD8^- (n=1) cases. Genetic alterations, including recurrent mutations and novel rearrangements, were identified in 8/10 (80%) of these lymphoproliferative disorders. The CD4⁺, CD4⁺/CD8⁺, and CD4^-/CD8^- cases harbored frequent alterations of JAK-STAT pathway genes (5/6, 82%); STAT3 mutations (n=3), SOCS1 deletion (n=1) and STAT3-JAK2 rearrangement (n=1), and 4/6 (67%) had concomitant mutations in epigenetic modifier genes (TET2, DNMT3A, KMT2D). Conversely, 2/4 (50%) of the CD8⁺ cases exhibited structural alterations involving the 3' untranslated region of the IL2 gene. Longitudinal genetic analysis revealed stable mutational profiles in 4/5 (80%) cases and acquisition of mutations in one case was a harbinger of disease transformation. The CD4⁺ and CD4⁺/CD8⁺ lymphoproliferative disorders displayed heterogeneous Th1 (T-bet⁺), Th2 (GATA3⁺) or hybrid Th1/Th2 (T-bet⁺/GATA3⁺) profiles, while the majority of CD8⁺ disorders and the CD4^-/CD8^- disease showed a type-2 polarized (GATA3⁺) effector T-cell (Tc2) phenotype. Additionally, CD103 expression was noted in 2/4 CD8⁺ cases. Our findings provide insights into the pathogenetic bases of indolent T-cell lymphoproliferative disorders of the gastrointestinal tract and confirm the heterogeneous nature of these diseases. Detection of shared and distinct genetic alterations of the JAK-STAT pathway in certain immunophenotypic subsets warrants further mechanistic studies to determine whether therapeutic targeting of this signaling cascade is efficacious for a proportion of patients with these recalcitrant diseases.