[2102] Potential Diagnostic Pitfalls Related to Bone Marrow Biopsy Quality in Staging Diffuse Large B-Cell Lymphoma

Eric Montgomery, Amber Chevalier, Vishala Neppalli. Roswell Park Cancer Institute, Buffalo, NY

Background: Diffuse large B-cell Lymphoma (DLBCL) is a common and an aggressive subtype of non-Hodgkin lymphoma (NHL). International Prognostic Indices (IPI) guide clinical management and prognostication at primary diagnosis. Morphologic evaluation of the bone marrow in combination with sensitive ancillary studies such as immunohistochemistry (IHC), flow cytometry (FCM) and molecular studies for B- cell clonality (IGH) are critical for staging DLBCL. Variability of marrow space involvement by DLBCL and sampling discrepancies can affect diagnostic outcome across these methods. In this study we looked at the frequency of discordant results across different diagnostic techniques, the effect of trephine core length on morphologic diagnostic outcome, and the potential influence of these discrepancies on staging of DLBCL.
Design: There were 174 DLBCL staging bone marrow biopsies from year 2003-2010, with concurrent FCM and IGH data available for review at RPCI. Length of the trephine core biopsies and the extent of marrow space involvement by DLBCL were recorded. FCM and IGH data was correlated with morphologic diagnosis. FCM and IGH assays were performed using standard laboratory protocols.
Results: Average length of trephine core biopsies was 8.4mm, range of 2mm to 50mm. 152/174 (87.4%) were of inadequate length (<15mm). Morphology, FCM and IGH were positive in 8/174 (4.6%), negative in 121/174 (69.5%), and discordant across the three methods in 45/174 specimens (25.8%). Within the discordant group, the trephine core biopsy was of inadequate length in 41/45 (91.1%), with a negative morphologic diagnosis in 35/45 specimens (77.7%). Clinical staging data was available in 36/45 among the discordant cases. 18/36 cases were assigned a Stage I-II status, of which 16/18 (89%) were of sub-optimal length and morphology for diagnosis, with a negative morphologic diagnosis in 17/18 (94%) cases.
Conclusions: Inadequate marrow trephine core biopsy length contributes significantly to discordant diagnostic data, creates interpretive pitfalls, and can lead to a false negative morphologic diagnosis in staging bone marrow biopsies. This diagnostic disparity can potentially lead to inaccurate clinical staging. The outcome of upstaging disease status based on positive ancillary data, independent of marrow morphology is unclear at this time.
Category: Quality Assurance

Monday, March 19, 2012 1:00 PM

Poster Session II # 264, Monday Afternoon


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