Ki-67 Labeling Indices in 'Classic' versus 'Blastoid' Mantle Cell Lymphomas--Proposed Cutoff Values for Routine Diagnostic Workup.

Shahid Pervez,Dreema Awan,Saroona Haroon

doi:10.7314/apjcp.2015.16.15.6591

Shahid Pervez, Dreema Awan + Show 1 more

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https://doi.org/10.7314/apjcp.2015.16.15.6591

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Abstract

Mantle-cell lymphoma (MCL) is a unique entity of peripheral B-cell lymphoma that has a discrete morphologic, immunologic, and genetic phenotype, with more common 'classic' and less frequent 'blastoid' and 'pleomorphic' variants, associated with an aggressive clinical course. The aim of this study was to analyze proliferation (Ki-67) indices of 'classic' (c-MCL) and 'blastoid' (b-MCL) variants of a cohort of MCL and to suggest cut off values for the Ki-67 proliferation index in these two subsets. MCL cases diagnosed over 4 1/2 years at Section of Histopathology, Department of Pathology and Laboratory Medicine, Aga Khan University Hospital, Karachi were retrieved and reviewed. Ki-67 labelling was scored and analysed. A total of 90 of cases of MCL were scrutinized. Mean age±SD was 60.2±12.5 years and the male to female ratio was 4:1, with 67 (75%) cases of c-MCL and 23 (25%) cases of b-MCL. Most samples were lymph node biopsies (n=68), whereas the remainder were from various extranodal sites The mean Ki-67 proliferation index was 29.5%±14.4% in classic variants and 64.4±15.2% for the blastoid variant, the difference being statistically significant (p=0.029). It was concluded that differential cut-off values of Ki-67 labeling may be used in more objective way to reliably classify MCL into classic or blastoid variants by diagnostic pathologists. We propose a <40 proliferative index to be suggestive of c-MCL and one of >50 for the blastoid variant.

Highlights

Mantle cell lymphoma (MCL) is a distinct type of B cell non-Hodgkin lymphoma (B-NHL) that accounts for approximately 3-10% of all non-Hodgkin lymphomas (NHL), (Swerdlow et al, 2008; Sader-Ghorra et al, 2014)
We propose a < 40 proliferative index to be suggestive of c-Mantle-cell lymphoma (MCL) and one of > 50 for the blastoid variant
Cyclin D1 staining is used as a surrogate marker for t(11; 14) and is positive in almost all cases of MCL

Summary

Introduction

Mantle cell lymphoma (MCL) is a distinct type of B cell non-Hodgkin lymphoma (B-NHL) that accounts for approximately 3-10% of all non-Hodgkin lymphomas (NHL), (Swerdlow et al, 2008; Sader-Ghorra et al, 2014). A more aggressive form, the blastoid-variant MCL (b-MCL), presents at an earlier age with significant short survival i.e. Mean survival of less than 20 months. The fact that patients with b-MCL show a higher proliferative rate warrants that this variant should be reliably categorized as an aggressive lymphoma (Klapper et al, 2009; Vose 2013). Mantle-cell lymphoma (MCL) is a unique entity of peripheral B-cell lymphoma that has a discrete morphologic, immunologic, and genetic phenotype, with more common ‘classic’ and less frequent ‘blastoid’ and ‘pleomorphic’ variants, associated with an aggressive clinical course. Conclusions: It was concluded that differential cut-off values of Ki-67 labeling may be used in more objective way to reliably classify MCL into classic or blastoid variants by diagnostic pathologists. We propose a < 40 proliferative index to be suggestive of c-MCL and one of > 50 for the blastoid variant

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