Detection of Nonhematologic Neoplasms by Routine Flow Cytometry Analysis

OBJECTIVES: We investigated the ability of routine flow cytometry (FC) to detect nonhematologic neoplasms (non-HN) using antibody panels routinely used for the diagnosis of hematologic neoplasms. METHODS: FC analyses of 4,000 various diagnostic samples were retrospectively reviewed to identify cases in which an aberrant, viable CD45-negative, nonhematologic neoplastic population was detected by FC panels designed to evaluate hematologic neoplasms. RESULTS: A total of 57 (1.4%) diverse non-HNs were identified, representing neuroendocrine tumors (33/57) and carcinomas (9/57), as well as other malignancies (15/57) such as sarcoma and melanoma. The majority of neoplasms were positive for at least one antibody, typically CD56 (43/51, 84.3%), followed by CD117 (15/34, 44.1%) and CD138 (6/33, 18.2%). CONCLUSIONS: Our findings highlight the importance of carefully inspecting CD45-negative events to identify non-HNs by routine FC analysis. This can help expedite further downstream immunophenotypic analysis of specimens and triage samples for appropriate genetic and molecular studies.