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Published on: October 30, 2010
Should the Reporting of Bone Marrow Positivity for Amyloid Be Revised? A Critical Assessment Based On 66 Biopsies
Sara Javidiparsijani1, Maria M Picken1
1From the Department of Pathology, Loyola University Medical Center, Maywood, Illinois. Dr Javidiparsijani is now with the Department of Hematopathology, NYU-Langone Health, New York, New York.
Context.—:
Amyloidoses are rare but heterogeneous disorders for which diagnosis is contingent upon the detection of deposits by Congo red stain and amyloid protein typing determines the treatment options.
Objective.—:
To address the reporting of bone marrow (BM) involvement by amyloid in relation to the spatial distribution of deposits and to explore whether the location of deposits may have clinical relevance.
Design.—:
We examined 66 BM biopsies positive for amyloid with regard to the location and type of amyloid, the percentage and clonality of plasma cells, other organ involvement, and relevant clinical information.
Results.—:
In 21 cases, amyloid deposits involved BM stroma, whereas 45 cases were nonstromal. All cases of stromal involvement were typed as AL amyloidosis (or presumed AL), whereas nonstromal involvement was associated with at least 3 types of amyloidosis: AL, ATTR, and AA. The initial diagnosis of amyloidosis was made in a BM specimen in 21 of 66 cases (31.8%). Plasma cells ranged from 1% to 80% (mean, 13.4%; median, 8%; <10% in 44 of 66 specimens [66.6%]) and were monoclonal in 58 of 66 cases (87.8%), and in 54 of 66 cases (81.8%) amyloid deposits were documented in at least one other organ.
Conclusions.—:
This study demonstrates that there is significant heterogeneity in the spatial distribution of amyloid in BM biopsy specimens with medullary, extramedullary, purely vascular, or combined involvement. Whereas stromal deposits were associated exclusively with AL, nonstromal and purely vascular deposits were seen in at least 3 types of systemic amyloidosis (AL, AA, and ATTR). We discuss the reporting of BM biopsy tissue positivity for amyloid deposits.
Insights
Amyloid deposits in bone marrow biopsies show varied spatial distribution. Stromal involvement is specific to AL amyloidosis, while nonstromal deposits indicate multiple amyloid types, impacting diagnosis and treatment.
Area of Science:
- Hematopathology
- Oncology
- Nephrology
Background:
- Amyloidoses are rare, heterogeneous disorders requiring accurate diagnosis for effective treatment.
- Bone marrow biopsy is crucial for detecting amyloid deposits and guiding therapeutic strategies.
Purpose of the Study:
- To analyze the spatial distribution of amyloid deposits in bone marrow (BM) biopsies.
- To investigate the clinical relevance of amyloid deposit location in BM.
Main Methods:
- Reviewed 66 bone marrow biopsies with amyloid deposits.
- Assessed amyloid type, deposit location (stromal vs. nonstromal), plasma cell characteristics, and other organ involvement.
Main Results:
- Amyloid deposits exhibited heterogeneous spatial distribution: medullary, extramedullary, vascular, or combined.
- Stromal involvement was exclusively associated with AL amyloidosis.
- Nonstromal and vascular deposits were linked to AL, AA, and ATTR amyloidosis types.
Conclusions:
- Bone marrow biopsy findings in amyloidosis display significant heterogeneity in deposit distribution.
- Spatial distribution of amyloid in BM biopsies can provide insights into amyloid type and potential clinical relevance.
