Central Nervous System Involvement in Peripheral T Cell Lymphoma

Diagnosis, prevention and treatment of central nervous system involvement in peripheral t-cell lymphomas

Non-Hodgkin lymphomas with T-cell immunophenotype encompass a heterogeneous group of infrequent neoplasms that follow variable clinical courses but prevalently include aggressive behavior and high mortality rates. The involvement of the central nervous system (CNS) is an uncommon event in T-cell lymphomas, with wide variability among the different disease entities. CNS can be affected either at initial diagnosis or at recurrence, and both forms are considered "secondary CNS T-cell lymphoma". Given the low incidence of secondary CNS T-cell lymphoma, related literature is sparse, contradictory, and primarily constituted by small case series and single case reports. However, reported studies uniformly suggest high mortality rates related to this event. Therefore, to improve our ability to identify high-risk patients and offer them successful CNS prophylaxis or timely and effective treatment once the event has occurred may prevent CNS-related T-cell lymphomas deaths. For example, some entities like aggressive adult T-cell leukemia/lymphoma, extranodal natural killer/T-cell lymphoma, and other peripheral T-cell lymphomas with involvement of two or more extranodal organs are prone to CNS dissemination and should be considered for personalized CNS prophylaxis. The level of evidence suggesting an increased risk of CNS recurrence for other T-cell lymphomas and for other risk factors is lower. Published case series show that, following the example of aggressive B-cell lymphomas, patients with T-cell lymphomas and putative increased CNS risk receive different forms of prophylaxis, mostly methotrexate and cytarabine delivered by intrathecal and/or intravenous routes, with varied success. To date, achievements in the treatment of CNS involvement in patients with aggressive B-cell lymphoma were not replicated in secondary CNS T-cell lymphomas, and identification of effective therapies remains an urgent research target. This review is focused on clinical findings, diagnosis, treatment, and prognosis of patients with T-cell lymphoma experiencing CNS dissemination either at presentation or relapse. It aims to provide logical and, oftentimes, evidence-based answers to the most common questions on the most probable risk factors to CNS involvement in patients with T-cell lymphoma, the indications and strategies to prevent this life-threating event, and the management of patients with CNS disease.

Recent Progress on Primary Central Nervous System Lymphoma-From Bench to Bedside

Primary central nervous system lymphoma (PCNSL) is a rare subtype of extra-nodal lymphoma. The high relapse rate of PCNSL remains a major challenge to the hematologists, even though patients exhibit high sensitivity to the methotrexate-based chemotherapeutic regimens. Recently, the advent of Bruton's tyrosine kinase inhibitor (BTKi) and CAR T treatment has made more treatment options available to a proportion of patients. However, whether BTKi monotherapy should be given alone or in combination with conventional chemotherapy is still a clinical question. The status of CAR T therapy for PCNSLs also needs to be elucidated. In this review, we summarized the latest progress on the epidemiology, pathology, clinical manifestation, diagnosis, and treatment options for PCNSLs.

Secondary parenchymal CNS involvement by lymphoma including rare types: Follicular and EBV-positive NK/T cell lymphoma, nasal type

BACKGROUND

Secondary CNS involvement by systemic lymphomas (SCNSL) is uncommon, but when it occurs, is usually due to diffuse large B cell lymphoma (DLBCL). Three recent unusual cases serve to highlight diagnostic challenges.

OBJECTIVE

To report SCNSL from DLBCL and two unusual lymphoma types: follicular lymphoma with high-grade transformation to DLBCL and NK/T cell lymphoma, nasal type (ENKL), nasal type.

RESULTS

SCNSL in the DLBCL case occurred at 7-year interval from primary in a 54-year-old woman who presented with stroke-like symptoms and a right postcentral gyrus 2.6 × 2.9 × 2.6 cm. mass. The follicular lymphoma occurred at 6-month interval in a 69-year-old woman with 1 month of diplopia and 2 weeks of cognitive decline; multifocal lesions involved temporal lobe, subependymal periventricular areas, brainstem, cerebellum, hypothalamus, corpus callosum and gyrus rectus. The ENKL occurred at 25-month interval from nasal biopsy in a 45-year-old man with 1 week of altered mental status; multifocal cerebral and brainstem lesions were identified. Histological features in cases 1 and 3 were identical to the primary lymphoma, with high-grade transformation to DLBCL in the follicular lymphoma.

CONCLUSION

Unusual features in our series include longer interval from primary to relapse in case 1 with DLBCL (usually <2 years of diagnosis), and SCNSL occurring from either follicular lymphoma or EKNL, nasal type (<6% of cases). Pathologists play an important role in excluding infectious, especially in cases with parenchymal lesions and characterizing the lymphoma type in SCNSL.

Primary Central Nervous System Involvement in Peripheral T-Cell Lymphoma: A Case Report

Primary central nervous system T-cell lymphoma (PCNSTL) is an extremely rare type of brain tumor. There are only few reports on the imaging findings of patients with PCNSTL. Herein, we report the imaging findings of a patient with peripheral T-cell lymphoma-not otherwise specified that presented with numerous small nodular and patchy strongly enhancing lesions on MRI.

Molecular Diagnostics in Lymphoid Neoplasms of the Central Nervous System

Primary lymphoid neoplasms of the central nervous system are rare tumors that span a wide range of histopathologic appearances and can overlap occasionally with non-neoplastic processes. Application of modern molecular techniques has not only begun to unravel their unique underlying biology but has also started to lay a valuable diagnostic and therapeutic framework for these frequently aggressive malignancies. This review summarizes the existing landscape of clinicopathologic and genomic features of lymphoid neoplasms that may arise primarily within the central nervous system.

Lymphomas arising in immune-privileged sites: insights into biology, diagnosis, and pathogenesis

Session 2 of the 2018 European Association of Hematopathology/Society for Hematopathology Workshop focused on lymphomas arising in immune-privileged sites: both lymphomas arising in the traditionally described "immune sanctuary" sites of the central nervous system (CNS) and testes, as well as those arising at sites of local immune privilege. Primary CNS large B cell lymphoma and primary testicular large B cell lymphoma were discussed, and the biology of these unique tumors was highlighted by several cases showing the classic mutation profile including MYD88 L265P and CD79B. The tendency of these tumors to involve both the CNS and testis was also reinforced by several cases. Four cases of low-grade B cell lymphomas (LGBCL) of the CNS were discussed. Two were classic Bing-Neel syndrome associated with LPL, and two were LGBCL with plasmacytic differentiation and amyloid deposition without systemic disease. Rare examples of systemic T and NK cell lymphomas involving the CNS were also discussed. Several cases of breast implant-associated anaplastic large cell lymphoma (BI-ALCL) were submitted showing the typical clinicopathologic features. These cases were discussed along with a case with analogous features arising in a patient with a gastric band implant, as well as large B cell lymphomas arising alongside foreign materials. Finally, large B cell lymphomas arising in effusions or localized sites of chronic inflammation (fibrin-associated diffuse large B cell lymphoma [DLBCL] and DLBCL associated with chronic inflammation) were described. The pathogenesis of all of these lymphomas is believed to be related to decreased immune surveillance, either innate to the physiology of the organ or acquired at a local site.

Gemcitabine, cisplatin, and dexamethasone (GDP) in combination with methotrexate and pegaspargase is active in newly diagnosed peripheral T cell lymphoma patients: a phase 2, single-center, open-label study in China

Peripheral T cell lymphomas (PTCL) are less responsive to anthracycline-containing regimen such as CHOP and carry a poor prognosis. In this prospective study, we investigated gemcitabine, cisplatin, and dexamethasone (GDP) combined with methotrexate (MTX) and pegaspargase (PEG-L) as front-line treatment in PTCL. Eligible newly diagnosed PTCL patients received 4 cycles of the GDP-ML chemotherapy every 28 days. After 4 cycles, responding patients continued to receive either autologous stem cell transplantation or the MTX/cytarabine (MA) regimen for consolidation. This trial is registered with www.chictr.org.cn (ChiCTR-ONC-12002055). A total of 65 patients were enrolled with a median follow-up of 38.5 months. The overall response rate (ORR) was 55.4%, and complete remission rate (CR) was 33.8%. The median overall survival (OS) was 16 months, and the 1-year and 2-year OS were 59.1% and 38.2%, respectively. The median PFS was only 8 months. The main adverse event was hematologic toxicity: 50% patients showed grade III/IV neutropenia. GDP-ML for the first-line treatment of PTCL patients is an effective induction regimen compared with standard CHOP, and the toxicity was more significant but acceptable. However, future studies exploring new drug combinations are warranted to overcome relapse after remission. ClinicalTrials.gov Identifier: NCT02987244.