Fine-Needle–Based Localization Techniques in Parathyroid Adenomas: A Retrospective Cohort Study of Histopathological Safety and Fibrosis Patterns

Background This study aimed to evaluate the association between fine-needle-based interventions widely used for preoperative and intraoperative localization of parathyroid adenomas and the development of post-excision stromal fibrosis and other histopathological changes that may mimic malignancy. Methods A total of 164 patients who underwent parathyroidectomy for primary hyperparathyroidism were retrospectively evaluated. The patients were divided into three groups according to the number of ultrasound-guided fine-needle interventions: needle-naive (Group 0, n  = 70), single-needle (Group 1, n  = 43), and two-needle (Group 2, n  = 51). All surgical specimens were histopathologically examined for the presence and extent of stromal fibrosis, thick fibrous capsule, fibrous bands, hemorrhage, hemosiderin deposition, capsular pseudoinvasion, tumor implantation, granulation tissue, and necrosis. Intergroup comparisons were performed using Welch’s t-test, the chi-square test, Fisher’s exact test, and Tukey post hoc analysis. Results The mean age of the patients was 54.8 ± 11.9 years, and 83.5% were female. Histopathological examination revealed fibrosis in 28 cases (17.1%), with a median stromal fibrosis percentage of 2.0% (1.0–10.0). The presence of fibrosis differed significantly among the needle-naive (12.9%), single-needle (30.2%), and two-needle (11.8%) groups (p = 0.028). Among cases with fibrosis, the stromal fibrosis percentage was higher in the needle-naive group than in the single- and two-needle groups (median 6.5% versus 2.0% and 2.0%, respectively, p = 0.045). No significant differences were observed in the remaining histopathological parameters (p > 0.05 for all). Conclusion In this study, the association between fibrosis and fine-needle interventions in parathyroid adenomas differed according to intervention frequency. Although the presence of fibrosis was more frequent in cases with a single needle intervention, the stromal fibrosis percentage in cases with fibrosis was higher in the needle-naive group. In contrast, the remaining histopathological parameters did not differ significantly among the needle groups. These findings suggest that fine-needle-based interventions have an acceptable histomorphological safety profile in parathyroid adenomas.