Background and objectives: Subcentimetric (defined as <1 cm at short axis) lymph nodes are considered benign and there is limited literature on the results of fine needle aspiration (FNA) of these nodes.
Methods: Endoscopic ultrasound (EUS) guided FNA was done on 189 lymph nodes in 166 patients with pyrexia of unknown origin (n = 113) or malignancy (n = 53). Subcentimetric lymph nodes (Group A) were compared to nodes with short axis diameter ≥1 cm (Group B). Data are shown as number, percentage, and median (25-75 interquartile range).
Results: There was no significant difference between Group A and Group B regarding site of lymph nodes (mediastinal in 73.6 and 72.5%, abdominal in 26.3 vs. 27.4%), number of slides (median 14 vs. 15), needle passes (median 2), and needle used (22 G needle in 85.5% vs. 69.9%). Group A had significantly lesser long axis diameter (1.5 [1.2-2] vs. 2.1 [1.6-2.9] cm) and short axis diameter (0.7 [0.6-0.8) vs. 1.4 [1.1-1.6] cm). A diagnosis (pathologic or reactive) could not be made in 2 (2.6%) and 11 (9.7%) lymph nodes in Group A and Group B, respectively (P = 0.078), due to inadequate material. Respective diagnoses in Group A and Group B were reactive lymphadenopathy (51.3% vs. 18.5%, P = 0.000), granulomatous lymphadenopathy (34.2% vs. 53%, P = 0.011), and malignancy (11.8% vs. 18.5%, P = 0.231). The lymph nodes with granulomatous and malignant change were significantly larger and had higher chances of having sharply demarcated borders as compared to reactive nodes.
Conclusion: EUS-guided FNA of subcentimetric lymph nodes have comparable results to larger nodes. Almost half of the subcentimetric lymph nodes are pathologic.