Flow cytometric immunophenotyping of bone marrow core biopsies: report of 8 patients with previously undiagnosed hematologic malignancy and failed bone marrow aspiration

To report a method for flow cytometric immunophenotyping (FCI) bone marrow (BM) core biopsies in patients with hematologic malignancies of the BM who present with a failed BM aspiration ("dry tap"). Core biopsy specimens of BM were obtained from 8 patients who presented with previously undiagnosed hematologic malignancies arising in (7 cases) or secondarily involving (1 case) the BM and a dry tap. Suspensions of the BM core biopsy specimens were prepared and analyzed by FCI methods. The FCI data were analyzed in conjunction with cytomorphologic, histologic, immunohistochemical, and cytogenetic findings in all cases to determine a final diagnosis. The prepared BM core suspensions were viable and allowed for a complete immunophenotype profile by FCI in all cases, resulting in a clear definition of the cell of origin of the hematologic malignancy. Because of lack of preservation of architectural features and the potential for artifactual alterations of the relative frequency of abnormal cells, the FCI data must always be correlated with histologic sections of the BM biopsy.