"Immunocytochemistry in Cytology: Myth or Reality": Unraveling the Myth - Immunocytochemistry Applications in Thyroid Lesions.

ABSTRACT

BACKGROUND: Fine-needle aspiration cytology serves as an important preoperative diagnostic tool for thyroid nodules. Despite its excellent diagnostic accuracy, diagnoses based solely on morphological observation can be challenging. Therefore, various ancillary diagnostic techniques have been applied, including immunocytochemistry (ICC). This review discusses the application and evaluation of ICC in thyroid fine needle aspiration. SUMMARY: Currently, three immunostaining preparation methods are available for cytological materials liquid-based cytology, cell block, and cell transfer. ICC proves valuable in scenarios such as tumour diagnosis, assessment of differentiation and grading of carcinomas, estimation of primary organs in metastatic carcinomas, and detection of gene abnormalities. However, ICC, while useful, is not as accurate as immunohistochemistry and is more difficult to evaluate. KEY MESSAGES If the pitfalls and limitations are understood and effectively navigated, ICC could play a significant role in decreasing the non-diagnostic rate, thus leading to more accurate and valuable diagnoses and reductions in the re-aspiration rate.