Hepatosplenic αβ T-cell lymphoma with myelodysplastic syndrome

An unusual case of hepatosplenic T-cell lymphoma-like unclassifiable T/NK-cell lymphoma accompanied by acute myeloid leukemia

We describe a case of unclassifiable T/NK-cell lymphoma with concomitant acute myeloid leukemia (AML). A 73-year-old Japanese man was diagnosed with AML by bone marrow smear, but the presence of splenomegaly and liver tumor was incompatible with AML. Splenectomy and hepatic resection were performed to resolve the thrombocytopenia and define the diagnosis. The pathological findings showed sinusoidal involvement of abnormal lymphoid cells that were CD3-positive but negative for T-cell receptor (TCR) rearrangement. Our case could not be categorized as hepatosplenic T-cell lymphoma because of the lack of immunohistological expression of TCR, despite the clinical similarity.

Bone Marrow Immunity and Myelodysplasia

Myelodysplastic syndrome (MDS) is characterized by an ineffective hematopoiesis with production of aberrant clones and a high cell apoptosis rate in bone marrow (BM). Macrophages are in charge of phagocytosis. Innate Immune cells and specific T cells are in charge of immunosurveillance. Little is known on BM cell recruitment and activity as BM aspirate is frequently contaminated with peripheral blood. But evidences suggest an active role of immune cells in protection against MDS and secondary leukemia. BM CD8⁺ CD28⁻ CD57⁺ T cells are directly cytotoxic and have a distinct cytokine signature in MDS, producing TNF-α, IL-6, CCL3, CCL4, IL-1RA, TNFα, FAS-L, TRAIL, and so on. These tools promote apoptosis of aberrant cells. On the other hand, they also increase MDS-related cytopenia and myelofibrosis together with TGFβ. IL-32 produced by stromal cells amplifies NK cytotoxicity but also the vicious circle of TNFα production. Myeloid-derived suppressing cells (MDSC) are increased in MDS and have ambiguous role in protection/progression of the diseases. CD33 is expressed on hematopoietic stem cells on MDS and might be a potential target for biotherapy. MDS also has impact on immunity and can favor chronic inflammation and emergence of autoimmune disorders. BM is the site of hematopoiesis and thus contains a complex population of cells at different stages of differentiation from stem cells and early engaged precursors up to almost mature cells of each lineage including erythrocytes, megakaryocytes, myelo-monocytic cells (monocyte/macrophage and granulocytes), NK cells, and B cells. Monocytes and B cell finalize their maturation in peripheral tissues or lymph nodes after migration through the blood. On the other hand, T cells develop in thymus and are present in BM only as mature cells, just like other well vascularized tissues. BM precursors have a strong proliferative capacity, which is usually associated with a high risk for genetic errors, cell dysfunction, and consequent cell death. Abnormal cells are prone to destruction through spontaneous apoptosis or because of the immunosurveillance that needs to stay highly vigilant. High rates of proliferation or differentiation failures lead to a high rate of cell death and massive release of debris to be captured and destroyed (1). Numerous macrophages reside in BM in charge of home-keeping. They have a high capacity of phagocytosis required for clearing all these debris.

Gamma-delta t-cell lymphomas

Gamma-delta T-cell lymphomas are aggressive and rare diseases originating from gamma-delta lymphocytes. These cells, which naturally play a role in the innate, non-specific immune response, develop from thymic precursor in the bone marrow, lack the major histocompatibility complex restrictions and can be divided into two subpopulations: Vdelta1, mostly represented in the intestine, and Vdelta2, prevalently located in the skin, tonsils and lymph nodes. Chronic immunosuppression such as in solid organ transplanted subjects and prolonged antigenic exposure are probably the strongest risk factors for the triggering of lymphomagenesis. Two entities are recognised by the 2008 WHO Classification: hepatosplenic gamma-delta T-cell lymphoma (HSGDTL) and primary cutaneous gamma-delta T-cell lymphoma (PCGDTL). The former is more common among young males, presenting with B symptoms, splenomegaly and thrombocytopenia, usually with the absence of nodal involvement. Natural behaviour of HSGDTL is characterised by low response rates, poor treatment tolerability, common early progression of disease and disappointing survival figures. PCGDTL accounts for <1% of all primary cutaneous lymphomas, occurring in adults with relevant comorbidities. Cutaneous lesions may vary, but its clinical behaviour is usually aggressive and long-term survival is anecdotal. Available literature on gamma-delta T-cell lymphomas is fractioned, mostly consisting of case reports or small cumulative series. Therefore, clinical suspicion and diagnosis are usually delayed, and therapeutic management remains to be established. This review critically analyses available evidence on diagnosis, staging and behaviour of gamma-delta T-cell lymphomas, provides recommendations for therapeutic management in routine practice and discusses relevant unmet clinical needs for future studies.

Hepatosplenic gamma-delta T-cell lymphoma

Hepatosplenic T-cell lymphoma (HSTL) is a rare and aggressive extranodal lymphoma derived mostly from cytotoxic γδ T-cells. The peak incidence is in adolescents and young adults, and is more common in males. Up to 20% of HSTL arise in the setting of chronic immune suppression, most commonly solid organ transplantation or prolonged antigenic stimulation. Patients present with systemic symptoms (fever), abdominal pain, weakness, and marked hepatosplenomegaly in the absence of lymphadenopathy. Patients usually manifest marked thrombocytopenia, often with anaemia and leucopenia, a leukemic phase, and bone marrow involvement in 80% of cases. Lactate dehydrogenase levels are usually markedly elevated. HSTL exhibits a marked chemoresistance to currently used regimens, a rapidly progressive behavior, and dismal prognosis. Patients with post-transplant HSTL exhibit an especially poor outcome. Standard treatment has yet to be established. Anthracycline-based chemotherapy is associated with a satisfactory response in two thirds of patients, but poor long-term results. Complete remission is extremely uncommon, and most patients die from lymphoma within two years of diagnosis. A prognostic correlation between outcome and degree of thrombocytopenia has been reported. Relapsing disease is usually chemorefractory and fast growing, and patients' performance status and clinical conditions are poor. These aspects, as well as the lack of drugs with proven activity against HSTL, render salvage treatment almost impossible. A few cases of HSTL successfully treated with autologous or allogeneic stem-cell transplantation have been reported. The use of 2'-deoxycoformycin and other targeted therapies, such as alemtuzumab, anti-γδ TCR monoclonal antibodies, and anti-CD44 therapy, have shown promising results in anecdotal reports.

Hepatosplenic T-cell lymphoma and inflammatory bowel disease

OBJECTIVE

This article reviews the current literature and knowledge about hepatosplenic T-cell lymphoma (HSTCL), providing an overview of the clinical features, a description of its pathology and immunophenotypic traits in relation to other lymphomas. In addition, we explore the history of reported cases of hepatosplenic T-cell lymphoma in relation to the possible existence of a causal relationship between infliximab use and HSTCL. The treatments for HSTCL will be briefly addressed.

METHODS

A comprehensive literature search using multiple databases was performed. Keyword search phrases including "lymphoma," "hepatosplenic T-cell lymphoma," "Inflammatory bowel disease," "6-mercaptopurine," and "infliximab" were used in various combinations. In addition references from published papers were reviewed as well.

RESULTS

There are over 200 reported cases of HSTCL. Only 22 cases of hepatosplenic T-cell lymphoma are associated with IBD treatment. Clinicians usually reserve immunomodulators and biologics for moderate to severe IBD cases. The ultimate goal of therapy is to control inflammation and therefore allow mucosal healing. IBD patients demonstrating mucosal healing are less likely to undergo surgery and experience complications related to their disease. We manipulate the immune system with corticosteroids, immunomodulators, and biologics, therefore causing bone marrow suppression. With bone marrow suppression, malignant degeneration may begin through selective uncontrolled cell proliferation, initiating HSTCL development in the genetically susceptible.

CONCLUSION

Hepatosplenic T-cell lymphoma is a rare disease, often with a poor outcome. With the increasing number of reported cases of HSTCL linked to the use of infliximab, adalimumab, and AZA/6-MP, there appears to be an undeniable association of HSTCL development with the use of these agents. This risk is unquantifiable. When considering the rarity of cases and the multiple complications with uncontrolled disease, however, the benefit of treatment far outweighs the risk.

Co-existent de novo myelodysplastic syndrome and T-cell non-Hodgkin lymphoma: a common origin or not?

The co-existence of de novo myelodysplastic syndrome (MDS) and non-Hodgkin lymphoma (NHL) prior to therapy is an extremely unusual finding. We report here a case of co-existent de novo MDS-refractory cytopenia with multilineage dysplasia and T-cell NHL, including clinical features, histopathological findings, molecular assessment, treatment course and outcomes. Other cases from the literature showing co-existence of both disorders are also reviewed; to date 19 similar cases have been reported. Among all cases (including the present patient), eight cases were diagnosed with de novo MDS and NHL simultaneously, which were considered to be true coincidences. The mechanisms responsible for the appearance of co-existence have not yet been ascertained, however in the present case a common chromosomal abnormality (20q deletion) was found in bone marrow and lymph node preparations. We conclude, therefore, that the co-existent de novo MDS and T-cell NHL seen in the present case may have a common origin.

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