Understanding splenic B-cell lymphoma/leukaemia with prominent nucleoli: Diagnosis, underpinnings for disease classification and future directions.

in British journal of haematology by Kikkeri N Naresh

TLDR

  • The WHO-HAEM5 classification introduced a new category, splenic B-cell lymphoma/leukaemia with prominent nucleoli (SBLPN), to address issues with the previous classification of splenic B-cell lymphomas. The study highlights the significance of the WHO-HAEM5 classification in addressing issues with the previous classification of splenic B-cell lymphomas, such as overlap with other indolent lymphomas and lack of consistent cytomorphological, immunophenotypic and genetic features. It offers practical guidance for diagnosis and discusses future directions in classifying splenic B-cell lymphomas, including the need for further research to refine the SBLPN category and establish more specific diagnostic criteria.

Abstract

The 5th edition of the WHO classification of haematolymphoid tumours (WHO-HAEM5) introduced a new category, splenic B-cell lymphoma/leukaemia with prominent nucleoli (SBLPN). The diagnostic entity B-cell prolymphocytic leukaemia (B-PLL) has been discontinued and the category of hairy cell leukaemia variant (HCLv) has been conceptually reframed. B-PLL and HCLv diagnoses were uncommon. Overlap existed between B-PLL and other indolent lymphomas like chronic lymphocytic leukaemia/small lymphocytic lymphoma (CLL/SLL). HCLv lacked consistent cytomorphological, immunophenotypic and genetic features. To address these issues, the WHO-HAEM5 classification has introduced SBLPN to serve as a temporary holding ground for entities that do not neatly fit into the existing classification. Cases previously classified as CD5-negative B-PLL and HCLv fall under the SBLPN category. Some splenic marginal zone lymphoma and splenic diffuse red pulp small B-cell lymphoma cases with higher number of medium or large nucleolated B cells would also be classified as SBLPN under the WHO-HAEM5. This review explores the rationale for discontinuing B-PLL and HCLv diagnoses. It then examines the concept of SBLPN, offers practical guidance for diagnosis and discusses future directions in classifying splenic B-cell lymphomas.

Overview

  • The study focuses on the WHO classification of haematolymphoid tumours (WHO-HAEM5) and its introduction of a new category, splenic B-cell lymphoma/leukaemia with prominent nucleoli (SBLPN).
  • The methodology used for the experiment includes a review of the literature on the WHO-HAEM5 classification and its impact on the diagnosis of splenic B-cell lymphomas.

Comparative Analysis & Findings

  • The study compares the outcomes observed under different experimental conditions or interventions detailed in the WHO-HAEM5 classification, specifically focusing on the discontinuation of B-PLL and HCLv diagnoses and the introduction of SBLPN as a temporary holding ground for entities that do not neatly fit into the existing classification.

Implications and Future Directions

  • The study highlights the significance of the WHO-HAEM5 classification in addressing issues with the previous classification of splenic B-cell lymphomas, such as overlap with other indolent lymphomas and lack of consistent cytomorphological, immunophenotypic and genetic features. It offers practical guidance for diagnosis and discusses future directions in classifying splenic B-cell lymphomas, including the need for further research to refine the SBLPN category and establish more specific diagnostic criteria.
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