Background: Flow cytometric analysis of bone marrow often is used as an adjunct to morphologic evaluation in the staging of patients with non-Hodgkin's lymphoma (NHL). The goal of this study was to define objectively the benefit of flow cytometry in this setting.
Methods: The authors reviewed retrospectively all bone marrow specimens submitted between January 1992 and December 1994 to the Washington University Department of Pathology for flow cytometric immunophenotyping to rule out NHL. Results of morphologic examination and flow cytometry were reviewed independently and the ability to detect bone marrow involvement compared.
Results: Two hundred and seventy-three bone marrow specimens from 190 patients with an established diagnosis of NHL were submitted for flow cytometric analysis at initial presentation, restaging, and/or recurrence. Morphologic evaluation was negative in 69%, positive in 23%, and equivocal in 8%. Flow cytometry was negative in all but 1 morphologically negative bone marrow specimens and 40% of morphologically involved bone marrow specimens. Two of 23 morphologically equivocal bone marrow specimens were positive by flow cytometry. An additional 86 specimens were obtained to rule out NHL in patients without an established diagnosis of NHL. The majority of patients had a history of human immunodeficiency virus infection, cytopenia, or unexplained fevers. Morphologically, one specimen was involved with NHL, 5 were equivocal, and 80 were negative. All specimens were negative by flow cytometry.
Conclusions: In this study, flow cytometric analysis improved the detection of NHL in bone marrow in only 3 of 273 samples, 2 of which were suspicious morphologically. Flow cytometry of bone marrow aspirates has a limited role in the routine staging and follow-up of patients with an established diagnosis of NHL.