Fine-needle-based localization techniques in parathyroid adenomas: a retrospective cohort study of histopathological safety and fibrosis patterns.

backgroundThis study aimed to evaluate the association between fine-needle-based interventions widely used for preoperative and intraoperative localization of parathyroid adenomas and development of post-excision stromal fibrosis and other histopathological changes that may mimic malignancy.

methodsA 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.

resultsThe mean age of the patients was 54.8 ± 11.9 years, and 83.5% were female. Fibrosis was identified in 28 cases (17.1%). In the unadjusted analyses, fibrosis frequency differed significantly among the groups (Group 0: 12.9%; Group 1: 30.2%; Group 2: 11.8%; p = 0.028). However, this association lost statistical significance after adjustment for potential confounding variables in multivariable logistic regression analysis (overall p = 0.10). Among cases with histologically detected fibrosis, the stromal fibrosis percentage was higher in Group 0 than in Groups 1 and 2 (p = 0.045). No significant between-group differences were observed in other histopathological findings that may mimic malignancy (p > 0.05 for all).

conclusionFine-needle-based localization techniques, including parathyroid hormone washout (PTH-WO) and radioguided occult lesion localization (ROLL), were not associated with prominent histopathological changes suggestive of malignancy in this cohort. Although fibrosis was more frequently observed in the needle intervention groups in the unadjusted analyses, this association was no longer significant after adjustment for potential confounding variables. In contrast, the stromal fibrosis percentage was higher in the needle-naive group; however, this analysis was based solely on the 28 cases with histologically detected fibrosis and should therefore be interpreted with caution. Overall, the findings suggest that PTH-WO and ROLL, when performed using standardized techniques and appropriate clinical indications, are not associated with prominent histopathological alterations. Larger prospective studies with long-term follow-up are needed to confirm these findings.