Flow Cytometric Analysis of Cerebrospinal Fluid Is Low Yield in Samples without Atypical Morphology or Prior History of Hematologic Malignancy.
Angela MB Collie, Eric D Hsi. Cleveland Clinic, OH
Background: Flow cytometric analysis (FCA) of cerebrospinal fluid (CSF) has utility in detecting central nervous system involvement by hematologic malignancies with greater sensitivity and specificity than cytology alone. Yet, often the CSF sample contains a limited number of viable cells. The purpose of this study is to identify characteristics of positive samples that will allow triaging of these suboptimal samples.
Design: Cases of CSF submitted for flow cytometry at our institution between 2007 and 2009 were identified. Retrospective review examined FCA diagnosis, cell concentration, lymphocyte percentage, blast percentage, antibody panel, and morphologic features. The electronic medical record was used to determine clinical features, cytopathologic diagnosis, history of hematologic malignancy, and future diagnosis of hematologic malignancy.
Results: 502 cases were examined involving 423 patients. Each case was classified into one of four diagnostic categories: positive, equivocal, negative and inadequate. A positive diagnosis of a lymphoproliferative disorder was made in 42 cases (8.4%), and a positive diagnosis of metastatic carcinoma was made in 2 cases (0.4%). The most common hematologic malignancies were B cell lymphoma, precursor B cell lymphoblastic leukemia/lymphoma, and acute myeloid leukemia. The positive cases showed atypical morphology, either blasts or atypical lymphocytes, in 98% of cases (41/42) in Wright stained slides screened by hematopathologists prior to FCA. There was also a history of a hematologic malignancy in 83% of positive cases (35/42). Cytopathology review was also positive in 88% of positive cases (22/25). 16 cases (3.2%) were classified as equivocal. 7 equivocal cases were diagnosed as a possible B-cell lymphoproliferative disorder due to low cell number; these 7 patients were later diagnosed clinically with CSF hematologic malignancies. 6 equivocal cases lacked B cell surface immunoglobulin; none of these patients had a future hematologic malignancy. 407 cases (81.2%) were negative. 28 negative cases had atypical morphology. Overall, the negative cases had significantly less cells compared to positive cases (p<0.05). 34 cases (6.8%) were classified as inadequate for diagnosis due to limited CD45 positive cells.
Conclusions: Flow cytometric analysis of CSF can be useful in the diagnosis of hematologic malignancies. This data supports a policy in which FCA of CSF is actively discouraged unless atypical cells/blasts are seen on Wright stained slides or a history of prior hematologic malignancy is present.
Tuesday, March 1, 2011 1:00 PM
Poster Session IV # 165, Tuesday Afternoon