A 24 year-old woman with relapsing brainstem manifestations and multiple focal brain lesions. Natural killer cell lymphoblastic lymphoma/leukemia

Primary Brainstem Lymphoma: A Population-Based Study

Background

Primary brainstem lymphoma (PBSL) is rare and malignant. An understanding of this disease is lacking. We aimed to characterize clinical features, estimate survival, and explore survival-related factors of PBSL.

Methods

Patients with a histological diagnosis of primary lymphoma in the brainstem (C71.7) from 1975 to 2016 were retrieved from the Surveillance, Epidemiology, and End Results (SEER) program. Log-rank tests and univariate and multivariate Cox proportional hazard analyses were used to identify survival-related factors.

Results

PBSL constituted 2.7% of brainstem malignancies. The median age of the PBSL patients was 59.5 years. Diffuse large B cell lymphoma (n = 49, 84.5%) was the most prevalent histology among the 58 cases with reported specific lymphoma subtype. The majority of PBSLs were localized (n = 46, 52.3%), at low Ann Arbor Stage (I/II, n = 63, 70.5%), and presented as a single primary (n = 71, 80.7%). Chemotherapy was applied in 50 (56.8%) cases. Three-year overall survival (OS) and disease-specific survival (DSS) rates were 42.7% and 53.5%, respectively. Multivariate analyses showed that independent predictive/prognostic factors for OS were age (P = 0.004), tumor number (P = 0.029), and chemotherapy (P = 0.001); DSS-related factors only included age (P = 0.014) and chemotherapy (P = 0.008).

Conclusions

We estimated survival rates for PBSL patients. Factors associated with OS and DSS were also identified. Our findings addressed the importance of chemotherapy in treating PBSL patients.

Lineage Assignment in Acute Leukemia: A Challenging Case in a Pediatric Patient

We report a case of a 2-year-old girl who was diagnosed with natural killer cell acute lymphoblastic leukemia and treated with an acute lymphoblastic leukemia chemotherapy regimen. Two months posttherapy, the disease relapsed with a myeloid immunophenotype. Complete response was then achieved with acute myeloid leukemia therapy followed by unrelated donor umbilical cord allogenic stem cell transplant. Retrospectively, reanalysis of the diagnostic specimen showed minimal myeloperoxidase expression that was called negative by conventional single parameter linear gating but better appreciated on histogram overlays. This case illustrates that even low levels of myeloperoxidase expression should be considered significant in lineage assignment in acute leukemia.

Natural Killer Cell Lymphoblastic Leukaemia/Lymphoma: Case Report and Review of the Recent Literature

Natural killer (NK) cell lymphoblastic leukaemia/lymphoma is a rare haemopoietic tumour currently defined in the 2008 WHO classification under the category of acute leukaemias of ambiguous lineage. A diagnosis of this type of leukaemia is considered in cases expressing CD56 along with immature T-cell-associated markers such as CD2 and CD7 with absence of B-cell and myeloid markers; in addition, blastic plasmacytoid dendritic cell leukaemia should be excluded. Prior to 2008, these precursor NK cell lymphoblastic leukaemias/lymphomas were categorized as myeloid/NK cell acute leukaemia with a phenotype identical to acute myeloid leukaemia with minimal differentiation. While the new classification has merit in having excluded myeloid expression, there is still persistent confusion in the literature and on a practical level with regard to precursor NK cell neoplasms. There is a paucity of recent case reports in the literature after the new WHO classification of this neoplasm. Due to the rarity of this neoplasm, an accurate pathological diagnosis is often difficult. In this article, we describe a case of precursor NK cell lymphoblastic leukaemia/lymphoma presenting with unique morphological features and conflicting immunophenotypes. We also review all case reports of this neoplasm after the WHO 2008 classification.