Non-invasive follicular thyroid neoplasm with papillary like nuclear feature (NIFTP) a case series on cytomorphological analysis

ABSTRACT

Non-invasive follicular thyroid neoplasm with papillary-like nuclear features (NIFTP) is an indolent thyroid neoplasm that poses diagnostic difficulty on preoperative fine-needle aspiration (FNA) cytology. In this retrospective study, eight cases diagnosed as NIFTP on histopathology between January 2019 and January 2022 were retrieved from the pathology department, and their corresponding FNA cytology smears were reviewed to assess cytomorphological features. The most frequent cytological findings observed in the current study were architectural abnormalities, predominantly crowded cell clusters with a microfollicular pattern. Nuclear features included nuclear overlapping and enlargement, eccentric nucleoli, irregular nuclear membranes, pale chromatin, nuclear grooves, and elongated nuclear contours. Intra-nuclear cytoplasmic inclusions were not identified in any of the cases. On cytological categorization, most cases were reported as suspicious for follicular neoplasm. These findings indicate that while certain architectural and nuclear features are consistently observed in NIFTP on cytology, they are not specific enough to allow a definitive preoperative diagnosis. Identification of NIFTP on FNA cytology therefore remains challenging, emphasizing the need for cautious interpretation and histopathological correlation.