Reliability of lymphoma diagnosis using combined cytologic preparations and core needle biopsy: A single-center analysis

Objectives: The diagnosis of lymphoma on cytologic preparations and core needle biopsies (CNBs) is often challenging due to limited material that precludes additional ancillary testing for accurate classification. We describe our institutional experience with patients who ultimately received a diagnosis of lymphoma using cytologic preparations and CNB material along with additional ancillary testing. Material and Methods: All patients whose cytology material (fluids, cytologic smears, and cell block) and CNB resulted in a diagnosis of lymphoma, atypical lymphoid population, or suspicious for lymphoma were retrieved. Diagnoses of lymphoma followed the established nomenclatures of the World Health Organization (WHO). For all cases, the ancillary test profiles were captured and summarized. Results: Of 389 cases identified, 17 (4.4%) were diagnosed as atypical lymphoid cells and 31 (7.9%) were suspicious for lymphoma resulting in an indeterminate rate of 12.3%. The rest of the malignant cases (341; 87.7%) were classified using 2017 WHO lymphoid classification system. Six low-grade and 26 high-grade B-cell lymphomas were not further classified because of limited tissue. B-cell lymphomas were the largest category (73.0%): Primarily diffuse large B-cell lymphoma (21.4%), followed by follicular lymphoma (17.5%) and chronic lymphocytic leukemia/small lymphocytic lymphoma (10.9%). A total of 140 cases (36.0%) had flow cytometry results, but 30 specimens (21.4%) were insufficient. Cytogenetic and molecular studies were performed for 78 cases (20.0%). Conclusion: Full classification of lymphomas is possible with combined cytologic preparations and CNB material and it is an attractive first sampling modality in the diagnostic process for this disease group.