Clinical, ultrasonographic, and cytological characteristics of niftp and postoperative outcomes: a retrospective cohort study.

PURPOSE: Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is an indolent thyroid neoplasm that cannot be definitively diagnosed before surgery. We aimed to describe the preoperative clinical, ultrasonographic and cytological characteristics of patients with NIFTP and to assess their postoperative outcomes.

METHODS

This retrospective cohort study included 165 adult patients with a histopathological diagnosis of NIFTP managed at a single tertiary center between January 2019 and July 2025. Demographic, biochemical, ultrasonographic (EU-TIRADS and ATA ultrasound risk stratification), cytological (Bethesda system) and follow-up data were analyzed. Outcome analyses were restricted to patients with isolated NIFTP.

RESULTS

Most patients were female (84.8%), with a mean age of 49.99 ± 12.61 years, and autoimmune thyroiditis was present in 26.7%. On ultrasound, 73.3% of nodules were classified as EU-TIRADS 2-3 and 73.9% as ATA low risk, with nearly identical distributions between the two systems. Among biopsied nodules, 41.8% fell into indeterminate Bethesda categories (III-IV), with Bethesda III being the most frequent, while 5.0% were classified as suspicious for malignancy (Bethesda V). Concurrent papillary thyroid carcinoma was identified in 41.2% of patients. Among the 97 patients with isolated NIFTP, no lymph node metastasis or structural recurrence occurred over a median follow-up of 28.0 (IQR 17.0-40.0; range 6-76) months, and only one patient received radioiodine.

CONCLUSION

NIFTP showed predominantly low-risk ultrasonographic and indeterminate cytological features, frequent coexisting carcinoma, and an excellent prognosis. These findings support conservative management, while the absence of dedicated follow-up recommendations warrants continued surveillance.