Noninvasive follicular thyroid neoplasm with papillary-like nuclear features

Histopathology_of_NIFTP

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features

Noninvasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is a recently recognized entity in the field of thyroid pathology. It represents a distinct category of thyroid nodules that were previously classified as encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC). The reclassification of NIFTP aims to reduce overtreatment of indolent thyroid nodules that do not exhibit aggressive behavior.

Characteristics

NIFTP is characterized by the presence of follicular growth pattern with nuclear features resembling papillary thyroid carcinoma, but lacking invasion of the tumor capsule or blood vessels. The nuclear features include nuclear enlargement, overlapping, and grooves, which are typical of papillary thyroid carcinoma. However, the absence of invasion distinguishes NIFTP from EFVPTC.

Diagnosis

Diagnosis of NIFTP is based on a combination of histological features, including the absence of invasion and the presence of nuclear features consistent with papillary thyroid carcinoma. Immunohistochemical markers such as thyroid transcription factor-1 (TTF-1) and thyroglobulin can also aid in the diagnosis of NIFTP.

Management

The management of NIFTP differs from that of papillary thyroid carcinoma. NIFTP is considered a low-risk lesion with an excellent prognosis, and therefore, conservative management such as observation or lobectomy may be sufficient. Total thyroidectomy and radioactive iodine ablation, which are commonly performed for papillary thyroid carcinoma, are usually not indicated for NIFTP.

Prognosis

Patients with NIFTP have an excellent prognosis, with a very low risk of recurrence or metastasis. The reclassification of NIFTP has led to a reduction in unnecessary surgeries and treatments for patients with this indolent thyroid nodule.