Significance of mast cells in diagnosis and grading of non-Hodgkin's lymphomas on fine-needle aspiration cytology

Abstract

Background: Information regarding the diagnostic role of mast cells in non-Hodgkin's lymphomas (NHLs) on fine-needle aspiration cytology (FNAC) is negligible. Aim of the Study: To assess the role of mast cells in diagnosing and distinguishing reactive lymphoid hyperplasia (RLH) versus low-grade NHL and low- versus high-grade NHLs on FNAC. Materials and Methods: Fine-needle aspirates from 50 reactive lymph nodes and 51 NHLs were studied. Cytologic smears of NHL cases and reactive controls were evaluated in a blinded manner. A standardized mast cell count (MCC) was performed on May–Grunwald–Giemsa smears of both “NHL” and “RLH” cases. MCC was compared between RLH and NHL groups and between low- and high-grade NHLs. Mann–Whitney U-test and Wilcoxon W-test were done for statistical analysis, takingP> 0.05 as statistically significant. A receptor operator characteristic curve was plotted to calculate the cutoffs for MCC. Results: Various morphologic types of NHL were encountered with 25 high-grade and 26 low-grade NHLs. The standardized MCC in RLH ranged from 0/25 hpf to 14/25 hpf (a mean MCC of 1.54/25 hpf), while for NHL group, it ranged from 0/25 hpf to 30/25 hpf (a mean MCC of 2.39/25 hpf). The difference in the median MCC between the two groups was statistically not significant (P > 0.05). Conclusion: Performing an MCC on cytologic smears may not be of significant practical value in distinguishing RLH versus low-grade NHL, and low/intermediate grade versus high-grade NHLs. Further larger studies are required to refute or support the cytodiagnostic role of mast cells in some specific subtypes of NHL.