Anaplastic Thyroid Carcinoma, Squamous Cell Carcinoma Pattern: Cytological Diagnosis According to the WHO 5th Edition Classification.

Anaplastic thyroid carcinoma (ATC) with squamous cell carcinoma pattern is a rare and highly aggressive thyroid malignancy that presents significant diagnostic challenges on cytology. According to the WHO 5th edition classification (2022), primary squamous cell carcinoma of the thyroid is no longer regarded as a distinct entity and is currently classified as a morphologic pattern/subtype of ATC.