AL amyloidosis with a localized B cell neoplasia

Christiane Stuhlmann-Laeisz,Christoph Röcken,Julius-Valentin Baumgart,Sandra Krüger,Ute Hegenbart,Ilske Oschlies,Stefan O Schönland

doi:10.1007/s00428-019-02527-7

Christiane Stuhlmann-Laeisz, Christoph Röcken + Show 5 more

Open Access

https://doi.org/10.1007/s00428-019-02527-7

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Abstract

Immunoglobulin light chain-derived (AL) amyloidosis may occur as a systemic disease usually with dismal prognosis and a localized variant with favorable outcome. We report 29 patients with AL amyloidosis and associated lymphoplasmacytic infiltrate spatially related to amyloid deposits. In 17 cases, the amyloid deposits were classified as ALλ and 12 as ALκ Histopathology in all cases showed relatively sparse plasma cells and B cells without tumor or sheet formation by the lymphoplasmacytic infiltrate. The B cells predominantly showed an immunophenotype of the marginal zone. In situ, hybridization revealed 17 cases with λ− and 10 with κ light chain restricted plasma cells, which was concordant with the AL subtype in each case. Clonal immunoglobulin heavy variable gene (IGHV) or κ light chain rearrangement was found in 23/29 interpretable cases. A single case harbored a MYD88L265P-mutation. Taken together, we detected 27 (93%) cases of AL amyloidosis with an associated light chain restricted and predominantly molecularly clonal plasma cell population. Clinical data were available in 18 patients. Five patients suffered from systemic lymphoma and two from systemic AL amyloidosis. The remaining cases were classified as localized with regard to both, the AL amyloidosis and the light chain restricted plasma cell population. To the best of our knowledge, we herein present the largest cohort of AL amyloidosis associated with a light chain restricted and predominantly molecularly clonal plasma cell population, which we designate as a distinct disease entity: “AL amyloidosis with a localized B cell neoplasia of undetermined significance”.

Highlights

Amyloid is characterized by the pathological deposition of peptides and proteins in diverse tissues and organs, which interferes with normal tissue and organ function
We report here on a prospective series of 29 patients with a>]. Immunoglobulin-light (AL) amyloidosis, who presented with a sparse lymphoplasmacytic infiltrate within or surrounding the amyloid deposits, some of which we subsequently classified as a BAL amyloidosis with a localized B-cell neoplasia of undetermined significance^
The current WHO-classification of Tumors of Hematopoietic and Lymphoid Tissue 2017 [6] classifies localized plasmacytic-differentiated B cell lymphoproliferations as plasmacytic-differentiated marginal zone lymphomas, presupposing that a small B cell component is detectable within the biopsy specimen

Summary

Introduction

Amyloid is characterized by the pathological deposition of peptides and proteins in diverse tissues and organs, which interferes with normal tissue and organ function. It consists of misfolded, insoluble, toxic proteinaceous aggregates, which are oriented in a β-sheet structure [1,2,3]. We report here on a prospective series of 29 patients with AL amyloidosis, who presented with a sparse lymphoplasmacytic infiltrate within or surrounding the amyloid deposits, some of which we subsequently classified as a BAL amyloidosis with a localized B-cell neoplasia of undetermined significance^

Materials and methods

28 F 64 Soft tissue

Discussion

Compliance with ethical standards