Morphologically occult systemic mastocytosis in bone marrow: clinicopathologic features and an algorithmic approach to diagnosis

Bone marrow (BM) biopsy specimens involved by systemic mastocytosis (SM) typically show multifocal, compact, dense aggregates of spindled mast cells (MCs). However, some cases lack aggregate formation and fulfill the World Health Organization 2008 criteria for SM, based on minor criteria. We identif...

Full description

Saved in:
Bibliographic Details
Published in:American journal of clinical pathology 2015-09, Vol.144 (3), p.493-502
Main Authors: Reichard, Kaaren K, Chen, Dong, Pardanani, Animesh, McClure, Rebecca F, Howard, Matthew T, Kurtin, Paul J, Wood, Adam J, Ketterling, Rhett P, King, Rebecca L, He, Rong, Morice, William G, Hanson, Curtis A
Format: Article
Language:English
Subjects:
Adult
Aged
Algorithms
Biopsy
Bone Marrow - pathology
Diagnosis, Differential
Female
Humans
Immunohistochemistry - methods
Interleukin-2 Receptor alpha Subunit - genetics
Male
Mast Cells - pathology
Mastocytosis, Systemic - genetics
Mastocytosis, Systemic - pathology
Middle Aged
Mutation - genetics
Proto-Oncogene Proteins c-kit - genetics
Tryptases - metabolism
Young Adult
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Bone marrow (BM) biopsy specimens involved by systemic mastocytosis (SM) typically show multifocal, compact, dense aggregates of spindled mast cells (MCs). However, some cases lack aggregate formation and fulfill the World Health Organization 2008 criteria for SM, based on minor criteria. We identified 26 BM cases of KIT D816V-mutated, morphologically occult SM in the BM. All patients had some combination of allergic/MC activating symptoms. Peripheral blood counts were generally normal. BM aspirates showed 5% or less MCs, which were only occasionally spindled. BM biopsy specimens showed no morphologic classic MC lesions. Tryptase immunohistochemistry (IHC) demonstrated interstitial, individually distributed MCs (up to 5%) with prominent spindling, lacking aggregate formation. MCs coexpressed CD25 by IHC and/or flow cytometry. Spindled MCs constituted more than 25% of total MCs in all cases and more than 50% in 20 of 26 cases. Morphologically occult involvement of normal-appearing BM by SM will be missed without appropriate clinical suspicion and pathologic evaluation by tryptase and CD25 IHC and KIT D816V mutation analysis. On the basis of these findings, we propose a cost-effective, data-driven, evidence-based algorithmic approach to the workup of these cases.
ISSN:1943-7722
DOI:10.1309/AJCPSGQ71GJQQACL