Noninvasive follicular thyroid neoplasm with papillary-like nuclear features: a problematic entity

Area of Science:

• Endocrinology
• Surgical Pathology
• Oncology

Background:

• Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) was previously termed noninvasive encapsulated follicular variant of papillary thyroid carcinoma.
• NIFTP represents 4.4-9.1% of papillary thyroid carcinomas globally, with lower incidence in Asian countries.
• Molecularly, NIFTP lacks high-risk mutations (BRAF, TERT, TP53) but frequently exhibits RAS mutations, similar to other follicular-pattern thyroid tumors.

Purpose of the Study:

• To provide a comprehensive overview of NIFTP, including its diagnosis, molecular characteristics, treatment, and prognosis.
• To highlight the diagnostic criteria and the role of preoperative assessments in suspecting NIFTP.
• To discuss the management strategies and long-term outcomes for NIFTP patients.

Main Methods:

• Diagnosis relies on postoperative histological examination using strict inclusion and exclusion criteria.
• Preoperative evaluation may involve ultrasonography, cytology, and molecular testing to raise suspicion.
• Treatment options include lobectomy or total thyroidectomy, with radioactive iodine and TSH suppression therapy not indicated.

Main Results:

• NIFTP has an extremely favorable prognosis, with effective treatment via lobectomy alone.
• The risk of adverse outcomes like lymph node or distant metastases is low but present.
• Histological confirmation post-surgery is essential for definitive NIFTP diagnosis.

Conclusions:

• NIFTP is a borderline thyroid tumor with an excellent prognosis and conservative treatment options.
• While not benign, NIFTP has a low risk of metastasis, making lobectomy a suitable primary treatment.
• Accurate histological diagnosis and understanding molecular features are crucial for managing NIFTP.